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Development, commissioning, and evaluation of a new intensity modulated minibeam proton therapy system

J. B. Farr, V. Moskvin, R. C. Lukose, S. Tuomanen, P. Tsiamas, W. Yao

Medical Physics, 15 July 2018


DOI: 10.1002/mp.13093

Purpose

To invent, design, construct, and commission an intensity modulated minibeam proton therapy system (IMMPT) without the need for physical collimation and to compare its resulting conformity to a conventional IMPT system.


Methods

A proton therapy system (Hitachi, Ltd, Hitachi City, Japan; Model: Probeat‐V) was specially modified to produce scanned minibeams without collimation. We performed integral depth dose acquisitions and calibrations using a large diameter parallel‐plate ionization chamber in a scanning water phantom (PTW, Freiburg, Germany; Models: Bragg Peak ionization chamber, MP3‐P). Spot size and shape was measured using radiochromic film (Ashland Advanced Materials, Bridgewater NJ; Type: EBT3), and a synthetic diamond diode type scanned point by point in air (PTW Models: MicroDiamond, MP3‐P). The measured data were used as inputs to generate a Monte Carlo‐based model for a commercial radiotherapy planning system (TPS) (Varian Medical Systems, Inc., Palo Alto, CA; Model: Eclipse v13.7.15). The regular ProBeat‐V system (sigma ~2.5 mm) TPS model was available for comparison. A simulated base of skull case with small and medium targets proximal to brainstem was planned for both systems and compared.


Results

The spot sigma is determined to be 1.4 mm at 221 MeV at the isocenter and below 1 mm at proximal distances. Integral depth doses were indistinguishable from the standard spot commissioning data. The TPS fit the spot profiles closely, giving a residual error maximum of 2.5% in the spot penumbra tails (below 5% of maximum) from the commissioned energies 69.4 to 221.3 MeV. The resulting IMMPT plans were more conformal than the IMPT plans due to a sharper dose gradient (90‐10%) 1.5 mm smaller for the small target, and 1.3 mm for the large target, at a representative central axial water equivalent depth of 7 cm.


Conclusions

We developed, implemented, and tested a new IMMPT system. The initial results look promising in cases where treatments can benefit from additional dose sparing to neighboring sensitive structures.

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Energy layer optimization strategies for intensity‐modulated proton therapy of lung cancer patients

M. Fuglsang Jensen, L. Hoffmann, J. B. B. Petersen, D. S. Møller

M. Alber


Medical Physics, 21 August 2018


DOI: 10.1002/mp.13139

Purpose

When treating lung cancer patients with intensity‐modulated proton therapy (IMPT), target coverage can only be guaranteed when utilizing motion mitigation. The three motion mitigation techniques, gating, breath‐hold, and dose repainting, all benefit from a more rapid application of the treatment plan. A lower limit for the ungated treatment time is defined by the number of energy layers in the IMPT plan. By limiting this number during treatment planning, IMPT could become more viable for lung cancer patients. We investigate to what extend the number of layers can be reduced in single‐field optimization (SFO) and multifield optimization (MFO) plans and which implications it has on the plan quality and robustness.


Methods

We have implemented three distinct layer‐reducing strategies in the treatment planning system Hyperion; constant energy steps, exponential energy steps, and an adaptive strategy, where the spot weights are exposed to a group sparsity penalty in combination with layer exclusion during optimization. Four levels of increasing layer removal are planned for each strategy. SFO and MFO plans with three treatment fields are created for eleven locally advanced NSCLC patients on the midventilation 4DCT phase to simulate a breath‐hold. A minimum dose to the target is ensured for each degree of layer reduction, reflecting the plan quality in the homogeneity index (HI). Plan quality was also assessed by a robustness evaluation, where the patient setup was shifted 2 mm or 4 mm in six directions.


Results

The three strategies result in very similar target coverages and robustness levels as a function of removed layers. The HI increases unacceptably for all the SFO plans after 50% layer removal as compared to the reference plan, while all the MFO plans are clinically acceptable with up to a highest removed percentage of 75%. The robustness level is constant as a function of removed layers. The SFO plans are significantly more robust than the MFO plans with all P‐values below 0.001 (Wilcoxon signed‐rank). The overall mean D98% CTV dose difference is at 2‐mm setup error amplitude: 0.7 Gy (SFO) and 1.9 Gy (MFO), and at 4 mm: 3.2 Gy (SFO) and 5.4 Gy (MFO), respectively.


Conclusions

The number of layers in MFO plans can be reduced substantially more than in SFO plans without compromising plan quality. Furthermore, as the robustness is independent of the number of layers, it follows that if the level of robustness is acceptable or enforced via robust optimization, MFO plans could be candidates for treatment time reductions via energy layer reductions.

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ONE SHOT - single shot radiotherapy for localized prostate cancer: study protocol of a single arm, multicenter phase I/II trial

Thomas Zilli, Marta Scorsetti, Daniel Zwahlen, Ciro Franzese, Robert Förster, Niccolò Giaj-Levra, Nikolaos Koutsouvelis, Aurelie Bertaut, Michel Zimmermann, Giuseppe Roberto D’Agostino, Filippo Alongi, Matthias Guckenberger, Raymond Miralbell


Radiation Oncology 201813:166

DOI: 10.1186/s13014-018-1112-0

Background

Stereotactic body radiotherapy (SBRT) is an emerging treatment alternative for patients with localized prostate cancer. Promising results in terms of disease control and toxicity have been reported with 4 to 5 SBRT fractions. However, question of how far can the number of fractions with SBRT be reduced is a challenging research matter. As already explored by some authors in the context of brachytherapy, monotherapy appears to be feasible with an acceptable toxicity profile and a promising outcome. The aim of this multicenter phase I/II prospective trialis to demonstrate early evidence of safety and efficacy of a single-fraction SBRT approach for the treatment of localized disease.


Methods

Patients with low- and intermediate-risk localized prostate cancer without significant tumor in the transitional zone will be treated with a single SBRT fraction of 19 Gy to the whole prostate gland with urethra-sparing (17 Gy). Intrafractional motion will be monitored with intraprostatic electromagnetic transponders. The primary endpoint of the phase I part of the study will be safety as assessed by CTCAE 4.03 grading scale, while biochemical relapse-free survival will be the endpoint for the phase II. The secondary endpoints include acute and late toxicity, quality of life, progression-free survival, and prostate-cancer specific survival.


Discussion

This is the first multicenter phase I/II trial assessing the efficacy and safety of a single-dose SBRT treatment for patients with localized prostate cancer. If positive, results of ONE SHOT may help to design subsequent phase III trials exploring the role of SBRT monotherapy in the exclusive radiotherapy treatment of localized disease.

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Diagnosis and management of radiation necrosis in patients with brain metastases

Balamurugan A. Vellayappan, Char Loo Tan, Clement Yong, Lih Kin Khor, Wee Yao Koh, Tseng Tsai Yeo, Jay Detsky, Simon Lo, Arjun Sahgal


Front. Oncol. 2018


DOI: 10.3389/fonc.2018.00395

The use of radiotherapy, either in the form of stereotactic radiosurgery (SRS) or whole-brain radiotherapy(WBRT), remains the cornerstone for the treatment of brain metastases(BM). As the survival of patients with BM is being prolonged, due to improved systemic therapy (i.e. for better extra-cranial control) and increased use of SRS (i.e. for improved intra-cranial control), patients are clinically manifesting late effects of radiotherapy. One of these late effects is radiation necrosis(RN). Unfortunately, symptomatic RN is notoriously hard to diagnose and manage. The features of RN overlap considerably with tumor recurrence, and misdiagnosing RN as tumor recurrence may lead to deleterious treatment which may cause detrimental effects to the patient. In this review, we will explore the pathophysiology of RN, risk factors for its development, and the strategies to evaluate and manage RN.

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Probabilistic dose distribution from interfractional motion in carbon ion radiation therapy for prostate cancer shows rectum sparing with moderate target coverage degradation

Probabilistic dose distribution from interfractional motion in carbon ion radiation therapy for prostate cancer shows rectum sparing with moderate target coverage degradation | Radiosurgery and Radiotherapy | Scoop.it
Daniel Bridges, Hidemasa Kawamura, Tatsuaki Kanai


PLOS x, August 31, 2018


DOI: 10.1371/journal.pone.0203289

Purpose

This observational study investigates the influence of interfractional motion on clinical target volume (CTV) coverage, planning target volume (PTV) margins, and rectum tissue sparing in carbon ion radiation therapy (CIRT). It reports dose coverage to target structures and organs at risk in the presence of interfractional motion, investigates rectal tissue sparing, and provides recommendations for lowering the rate of toxicity. We also propose probabilistic DVH based on cone-beam computed tomography (CBCT) table shifts from photon therapy for consideration in bone-matching CIRT treatment planning to represent probable dose to our CIRT patient population.


Methods

At Gunma University Hospital intensity-modulated x-ray therapy (IMXT, aka IMRT) prostate cancer patients are positioned on a table which is shifted twice based on CBCT to align bones and then align prostate tissue to isocenter. These shifts thereby contain interfractional motion. A total of 1306 such table shifts from 85 patients were collected. Normal probability distributions were fit to the difference between bone-matching and prostate-matching CBCT-to-planning CT table shifts (i.e. interfractional motion). Between 2011 and 2016 CIRT prostate patients were treated with three beams to PTV1 (lateral-opposing and anterior) one per day for 9 fractions and two beams for a boost PTV2 (lateral-opposing) one per day for 7 fractions for a prescribed total of 57.6 Gy(RBE) as follows: PTV1 extends the prostate contour by 10/10, 5/10, 6/6 mm in the right/left, posterior/anterior, and superior/inferior directions, respectively, and the proximal seminal vesicles contour by 5 mm superiorly and inferiorly, 3 mm right and left. PTV2 reduces PTV1 posteriorly along a straight line to exclude the rectum and reduces the superior and inferior margins by 6 mm. Probable interfractional motion for 40 patients was simulated using each patient’s own beam data as follows: The previously fit normal probability distributions were randomly sampled 2000 times per patient, and the five beams were shifted and summed with the same relative weighting as in the 16-fraction regimen. The resulting dose distribution was then scaled back down by 16/2000 to match the prescribed number of fractions. We then analyzed the resulting doses to contoured structures.


Results

Probable dose to rectum is substantially less than planned: For example, mean+-standard deviation D2% for planned and probable DVH is 51+-1.9 and 45+-2.4, respectively. Cumulative DVH show mean CTV fraction receiving a given probable dose is less than the mean fraction receiving the corresponding planned dose for doses larger than 52 Gy(RBE), up to 19% less at 57.4 Gy(RBE). Our PTV1 margins generally cover 95% of interfractional motion but seminal vesicles and inferior prostate receive less dose than planned due to insufficient PTV2 margins.


Conclusion

Assuming rigidly shifting interfractional motion around the prostate region and neglecting minor changes in soft tissue stopping power, interfractional motion resulted in target underdosing but better tissue sparing in all cases. Given our low rates of relapse and recurrence, it appears less curative dose is needed than previously thought or else current planning target margins may be excessive: Planning target volumes should be reconsidered with the adoption of dose verification methods. Our probable dose distributions quantify expected dose for future dose verification studies.

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Radiation therapy in lung cancer: Recent trends and future directions

Daniel R. Gomez

Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; January 8-11, 2018; San Diego, CA

DOI: 10.1158/1557-3265.AACRIASLC18-IA31

Radiation techniques for lung cancer have evolved substantially over the past decade. While previously many patients were treated with 3D conformal therapy, with large uniform margins placed to estimate respiratory motion in the “average” tumor, patients are now simulated with sophisticated, real-time monitoring of internal motion such that treatment volumes can be individualized to maximize normal tissue sparing through image-guided radiation therapy (IGRT). In addition, many patients are now treated with intensity-modulated radiation therapy (IMRT), which has served to drastically improve conformality in select cases and increase the proportion of patients in which high doses are achievable. Concurrent with these advances, proton beam therapy (PBT) has been implemented in a limited number of centers, with the hope of utilizing the dosimetric distribution advantage of the Bragg Peak to further reduce toxicity. The role of PBT in both early-stage and locally advanced non-small cell lung cancer continues to be defined, as results from a phase II multicenter randomized trial predominantly in patients with stage II-III disease did not demonstrate superiority with PBT and concurrent chemotherapy when compared to similar regimens with IMRT. Finally, there have been much data produced with regard to dosing regimens. In early-stage disease, there has been increased implementation of stereotactic ablative body radiation (SABR), with prospective data emerging for both peripheral and central lesions. In the locally advanced setting, results from RTOG 0617 demonstrated no difference when comparing 60 Gy vs. 74 Gy in the setting of chemoradiation. There has also been a trend towards hypofractionation for patients who are unable to tolerate concurrent chemoradiation or those with oligometastatic disease, yet the benefit of hypofractionated radiation sequentially vs. combined modality treatment will need to be further assessed in prospective randomized trials, particularly in the era of immunotherapy.

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Innovation in online hadrontherapy monitoring: An in-beam PET and prompt-gamma-timing combined device

Innovation in online hadrontherapy monitoring: An in-beam PET and prompt-gamma-timing combined device | Radiosurgery and Radiotherapy | Scoop.it
V. Ferrero, P. Cerello, E. Fiorin, V. Monaco, M. Rafecas, R. Wheadon, F. Pennazio


Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 31 August 2018


DOI: 10.1016/j.nima.2018.08.065

Quality assurance in particle therapy is an open issue that can be addressed with reliable monitoring techniques, such as in-beam PET and prompt-gamma-timing (PGT). In-beam PET is able to provide online feedback on the particle range by detecting the radiation related to the
activity, while PGT relies on the time-of-flight (TOF) of prompt photons. The I3PET (In-beam PET Innovative Imaging) project is developing a novel scanner demonstrator that combines in-beam PET and PGT within the same detector, exploiting the potential synergy of these two techniques.

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Safety of catheter-free VT ablation: Dose-dependent LVEF changes after proton beam therapy of the LV in a porcine model

Safety of catheter-free VT ablation: Dose-dependent LVEF changes after proton beam therapy of the LV in a porcine model | Radiosurgery and Radiotherapy | Scoop.it
S Hohmann A J Deisher A Suzuki H Konishi M E Rettmann H I Lehmann J Kruse K D Parker L K Newman M G Herman D L Packer

European Heart Journal, Volume 39, Issue suppl_1, 1 August 2018, ehy564.P298,


DOI: 10.1093/eurheartj/ehy564.P298

Background: Cardiac radiosurgery using methods established in radiation oncology has emerged as a promising tool for catheter-free arrhythmia ablation. Compared to x-rays, particle beams offer unique physical properties allowing to deliver less dose to organs at risk. Data on cardiac effects of radiation is derived mainly from collateral exposure in cancer treatment where single myocardial fractions are low. Here we report the dose effects on cardiac function of a single fraction ablative proton beam therapy of the left ventricle (LV) in a porcine model with up to 40 weeks follow-up.

Methods: 20 domestic pigs were treated with pencil-beam scanned proton therapy. Treatment planning was guided by end-expiration cardiac-gated 4D CT. Structures of interest were contoured on the 70% phase (diastolic) contrast-enhanced CT. Treatment planning and dose calculations reported were performed on the averaged 4D CT using the clinical treatment planning software. Between 1 and 3 transmural targets of various volumes were defined at arbitrary locations in the LV myocardium. Proton delivery was gated to expiration. Follow-up duration varied to allow for tissue analysis at different times. Cardiac MRIs were obtained at intervals of 4 weeks. LV ejection fraction (LVEF) was calculated from a stack of short axis 4D balanced steady-state gradient echo sequence MR images (slice thickness 8 mm).

Results: Of 20 animals treated (3 targets at 40 Gy, n=8; 2 targets at 30 Gy, n=4; 1 target at 40 Gy, n=8), 6 died suddenly during follow-up (all in the 3-target group). Myocardial volumes receiving at least 10 Gy (mean±SD) were 48±9 cm3 in the 3-target group, 24±5 cm3 in the 2-target group and 12±4 cm3 in the 1-target group.

105 cardiac MRIs were analyzed. LVEF over time was largely stable in the 1- and 2-target groups but declined at approximately 90 days in the 3-target group. To compensate for daily variations in LVEF caused by loading conditions and autonomic tone, all LVEF measurements in a single animal obtained before 90 days were averaged and compared to the average of all measurements obtained after 90 days. The decline in LVEF in individual animals was strongly correlated with the myocardial volume irradiated (Pearson's r = -0.93, p<0.001, for the volume receiving more than 10 Gy). A decline in LVEF of more than 10 percentage points was observed if more than 35% of left ventricular myocardium had been exposed to at least 10 Gy.

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Postsurgical Salvage Radiosurgery for Nonfunctioning Pituitary Adenomas Touching/Compressing the Optic Chiasm: Median 13-Year Postirradiation Imaging Follow-up Results

Postsurgical Salvage Radiosurgery for Nonfunctioning Pituitary Adenomas Touching/Compressing the Optic Chiasm: Median 13-Year Postirradiation Imaging Follow-up Results | Radiosurgery and Radiotherapy | Scoop.it
Masaaki Yamamoto, Hitoshi Aiyama, Takao Koiso, Shinya Watanabe, Takuya Kawabe, Yasunori Sato, Yoshinori Higuchi, Bierta E Barfod, Hidetoshi Kasuya

Neurosurgery, nyy357, 30 August 2018


DOI: 10.1093/neuros/nyy357

BACKGROUND

There is little information on long-term outcomes after salvage treatment by either surgery or stereotactic radiosurgery (SRS) for patients with recurrent/residual nonfunctioning pituitary adenomas (NFPAs).


OBJECTIVE

To reappraise the efficacy and safety of SRS for patients with NFPAs touching/compressing the optic apparatus (OA).


METHODS

We studied 27 patients (14 females, 13 males; mean age: 61 [range, 19-85] yr) who underwent SRS between 1998 and 2008 for NFPAs with such condition. The median tumor volume was 4.9 (range, 1.8-50.8) cc. To avoid excess irradiation to the OA, the lower part of the tumor was covered with a 50% or a 60% isodose gradient, ie 49% to 98% (mean, 84%; median, 88%) of the entire tumor received the selected doses. Median doses at the tumor periphery/OA were 7.6/11.0 (interquartile range [IQR], 5.8-9.1/10.1-11.8) Gy.


RESULTS

Seven patients (26%) were confirmed to be deceased due to unrelated diseases at a median post-SRS period of 149 (IQR, 83-158) mo. Follow-up magnetic resonance imaging (MRI) showed tumor growth in 2 patients (7%) at the 11th and 134th post-SRS month; the former underwent surgery and the other SRS. Excluding these 2 patients, the latest follow-up MRI examinations, performed 13 to 238 (median: 168, IQR: 120-180) mo after SRS, showed no size changes in 5 (19%) and shrinkage in 20 (74%) patients. Cumulative incidences of tumor growth control were 96.3% and 91.8% at the 120th and 180th post-SRS month. None of our patients developed subjective symptoms suggesting SRS-induced optic neuropathy or endocrinological impairment.


CONCLUSION

In patients with NFPAs touching/compressing the OA, SRS achieves good long-term results.

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Local response and pathologic fractures following stereotactic body radiotherapy versus three-dimensional conformal radiotherapy for spinal metastases - a randomized controlled trial

Tanja Sprave, Vivek Verma, Robert Förster, Ingmar Schlampp, Katharina Hees, Thomas Bruckner, Tilman Bostel, Rami Ateyah El Shafie, Thomas Welzel, Nils Henrik Nicolay, Jürgen Debus,  Harald Rief


BMC Cancer 2018 18:859

DOI: 10.1186/s12885-018-4777-8

Background

This was a prespecified secondary analysis of a randomized trial, which analyzed bone density following stereotactic body radiotherapy (SBRT) versus conventional three-dimensional conformal radiotherapy (3DCRT) as part of palliative management of painful spinal metastases.


Methods

Fifty-five patients were enrolled in this single-institutional randomized exploratory trial (NCT02358720). Participants were randomly assigned to receive SBRT (single-fraction 24 Gy) or 3DCRT (30 Gy/10 fractions). Quantitative bone density was evaluated at baseline, 3 and 6 months in both irradiated and unirradiated spinal bodies, along with rates of pathologic fractures and vertebral compression fractures.


Results

As compared to baseline, bone density became significantly higher at 3 and 6 months following SBRT by a median of 33.8% and 72.1%, respectively (p < 0.01 for both). These figures in the 3DCRT cohort were 32.9% and 41.2%, respectively (p < 0.01 for both). There were no statistical differences in bone density between SBRT and 3DCRT at 3 (p = 0.629) or 6 months (p = 0.327). Subgroup analysis of osteolytic metastases showed an increase in bone density relative to baseline in the SBRT (but not 3DCRT) arm. Bone density in unaffected vertebrae did not show substantial changes in either group. The 3-month incidence of new pathological fractures was 8.7% in the SBRT arm vs. 4.3% in the 3DCRT arm.


Conclusions

Despite high ablative doses in the SBRT arm, the significant increase in bone density after 3 and 6 months was similar to that of 3DCRT. Our trial demonstrated a moderate rate of subsequent pathological fracture after SBRT. Future randomized investigations with larger sample sizes are recommended.

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Targeting the vasculature of tumours: combining VEGF pathway inhibitors with radiotherapy

Chryso Kanthou, Gillian Tozer


The British Journal of Radiology, September 05, 2018


DOI: 10.1259/bjr.20180405

The development of blood vessels by the process of angiogenesis underpins the growth and metastasis of many tumour types. Various angiogenesis inhibitors targeted against vascular endothelial growth factor A (VEGF-A) and its receptors have entered the clinic more than a decade ago. However, despite substantial clinical improvements, their overall efficacy proved to be significantly lower than many of the pre-clinical studies had predicted. Antiangiogenic agents have been combined with chemotherapy, radiotherapy and more recently immunotherapy in many pre-clinical and clinical studies in an effort to improve their efficacy. To date, only their use alongside chemotherapy is approved as part of standard treatment protocols. Most pre-clinical studies have reported improved tumour control from the addition of antiangiogenic therapies to radiotherapy and progress has been made in unravelling the complex mechanisms through which VEGF inhibition potentiates radiotherapy responses. However, the efficacy of this combination is variable, and many questions still remain as to how best to administer the two modalities to achieve optimal response and minimal toxicity. One important limiting factor is that, unlike some other targeted therapies, antiangiogenic agents are not administered to selected patient populations, since biomarkers for identifying responders have not yet been established. Here, we outline VEGF biology and review current approaches that aim to identify biomarkers for stratifying patients for treatment with angiogenesis inhibitors. We also discuss current progress in elucidating mechanisms of interaction between radiotherapy and VEGF inhibitors. Ongoing clinical trials will determine whether these combinations will ultimately improve treatment outcomes for cancer patients.

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Feasibility of radiotherapy in nonagenarian patients: a retrospective study

L. Kocik, H. Geinitz, C. Track, M. Geier, C. Nieder


Strahlentherapie und Onkologie, pp 1–7, 30 August 2018


DOI: 10.1007/s00066-018-1355-6


Purpose

Specific information about radiation therapy in nonagenarians is limited. In order to shed more light on the feasibility of radiotherapy in this challenging subgroup, a retrospective study was performed.


Methods

The data of 93 consecutive patients receiving irradiation treatment at the Department of Radiation Oncology, Ordensklinikum Linz Barmherzige Schwestern between June 2005 and December 2016 were analyzed. Patient- and treatment-related factors were extracted from the patient records. Overall survival (OS) was defined as time from irradiation to death or last follow-up. The survival rates were analyzed using the Kaplan-Meier method and log-rank test.


Results

The study population of 93 patients was between 90 and 99 years old (median 91 years). It included 59 women (63%) and 34 men (37%). Of these, 38 (41%) received definitive radiotherapy, 14 (15%) received neoadjuvant or adjuvant radiotherapy, whereas a palliative regimen was prescribed in 44% of the cases (n = 41). In all, 79 patients (85%) were able to complete their prescribed course of radiotherapy. While 16 (17%) patients reported grade 2 toxicities or higher, 4 had ≥grade 3 side effects (4%). The median survival was significantly higher in patients treated with adjuvant, neoadjuvant or definitive radiotherapy (13.8 months) compared to patients treated with palliative radiotherapy (3.6 months; p < 0.001).


Conclusion

Even in patients managed without preradiotherapy comprehensive geriatric assessment, carefully planned fractionated radiotherapy was feasible and resulted in acceptable rates of acute toxicities.

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Experimental set-up for FLASH proton irradiation of small animals using a clinical system

Annalisa Patriarca, Charles Fouillade, Michel Auger, Frédéric Martin, Frédéric Pouzoulet, Catherine Nauraye, Sophie Heinrich, Vincent Favaudon, Samuel Meyroneinc, Rémi Dendale, Alejandro Mazal, Philip Poortmans, Pierre Verrelle, Ludovic De Marzi


International Journal of Radiation Oncology*Biology*Physics, 2018


DOI: 10.1016/j.ijrobp.2018.06.403

Purpose

Recent in vivo investigations have shown that short pulses (FLASH) of electrons are less harmful to healthy tissues, but just as efficient as conventional dose-rate radiation to inhibit tumor growth. In view of the potential clinical value of FLASH and the availability of modern proton therapy infrastructures to achieve this goal, we herein describe a series of technological developments required to investigate the biology of FLASH irradiation, using a commercially available clinical proton therapy system.


Methods and materials

Numerical simulations and experimental dosimetric characterization of a modified clinical proton beamline, upstream from the isocenter were performed with Monte Carlo toolkit and different detectors. A single scattering system was optimized together with a ridge filter and a high current monitoring system. In addition, a submillimetric set-up protocol based on image-guidance using a digital camera and an animal positioning system was also developed.


Results

The dosimetric properties of the resulting beam and monitoring system were characterized: linearity with dose rate and homogeneity for a 12x12 mm2 field size were assessed. Dose rates exceeding 40 Gy/s at energies between 138 and 198 MeV were obtained, enabling uniform irradiation for radiobiology investigations on small animals in a modified clinical proton beam line.


Conclusion

This approach will enable us to conduct FLASH proton therapy experiments on small animals, specifically for mouse lung irradiation. Dose rates exceeding 40 Gy/s were achieved, which was not possible with the conventional clinical mode of the existing beamline.

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Proton minibeams spare critical brain structures

Proton minibeams spare critical brain structures | Radiosurgery and Radiotherapy | Scoop.it
By Cynthia E Keen

A team at St. Jude Children’s Research Hospital has developed and validated a new intensity-modulated minibeam proton therapy (IMMPT) system. The system is designed to improve high-dose conformity at mid-depths compared with current pencil-beam scanning proton therapy systems. It may be able to improve treatments for brain tumours by delivering more precisely targeted radiation and reducing dose to surrounding normal tissues (Med. Phys. 10.1002/mp.13093).

Intensity-modulated proton therapy (IMPT) systems utilize individual beamlets that have optimized intensities to provide a balance between target dose and dose to normal tissues. They offer improved efficiency, proximal dose sparing and flexible applications compared with legacy double-scattering delivery systems. Improvements have reduced spot sizes to around 3 mm.

To reduce spot sizes further, field collimation is being utilized to improve target conformity and penumbra, the region at the edges of a radiation beam where a rapid dose reduction occurs. To simplify this process, the research team, led by Jonathan Brent Farr, aimed to create a system that produces much smaller clinical proton beamlets without the need for physical collimation.

Farr and colleagues modified a proton therapy system in regular clinical use in the hospital’s Red Frog Events Proton Therapy Center. They made two modifications to the system’s fixed horizontal beamline – adding and activating a vertical scraper to achieve a smaller beam size extracted from the synchrotron, and adopting a thinner vacuum window at the end of the beam line in the scanning nozzle – to enable IMMPT delivery using scanned minibeams. They also improved the proton spot position monitor and patient positioner accuracy to support clinical IMMPT delivery.

MR Safe 4D Motion QA for Planning, Adaptive MRgRT and SimulationAdvertisementThe researchers performed integral depth dose (IDD) acquisitions and calibrations, and compared IDDs, spot profiles and transmission chamber energy calibration curves with those from the regular system. They developed and validated Monte Carlo models and used these to produce spot profiles and IDDs. These were then imported into a commercial treatment planning system for dose model fitting, testing and validation.

Two patient plans were developed for a simulated base-of-skull case with small and medium targets proximal to the brainstem: one using a nominal discreet spot-scanning system and the other using the minibeam. The team compared these using dose difference and dose volume histogram analysis. The minibeam patient plan was also evaluated using the department’s standard patient-specific quality assurance programme.

The authors reported that the differences between 96 IDD measurements for the minibeam treatment compared with the standard spot commissioning data were indistinguishable. “The spot sigma is determined to be 1.4 mm at 221 MeV at the isocentre and below 1 mm at proximal distances,” they wrote, adding that “the treatment planning system [data] fit the spot profiles closely, giving a residual error maximum of 2.5% in the spot penumbra tails from 69.4 to 221.3 MeV.”

The resulting IMMPT plans delivered superior target conformity and brainstem sparing for both the small and medium targets. The authors attributed this to a steeper dose gradient compared with IMPT.

Farr tells Physics World that the IMMPT system has received 510(k) clearance from the US Food and Drug Administration and is in routine clinical use at St. Jude. “Currently, the physician-scientists are using the superior dose sparing properties of the minibeam to enhance the care of children with relatively small brain tumours abutting critical structures like the brain stem and optic nerves,” he says.

“An upcoming investigation using the IMMPT system to treat a range of ocular tumours is under development. Here, the additional sparing properties of the minibeam may be used to preserve orbital bone growth for the affected children,” he adds.

Farr, currently director of medical physics at Advanced Oncotherapy, a proton therapy system company headquartered in London, believes that the clinical use of proton minibeams will increase over time. He and his colleagues at Advanced Oncotherapy are working to investigate and develop proton minibeams to yet higher conformity.

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Out-of-field doses from secondary radiation produced in proton therapy and the associated risk of radiation-induced cancer from a brain tumor treatment

Oscar Ardenfors, Alexandru Dasu, Jan Lillhök, Linda Persson, Irena Gudowska


Physica Medica, Volume 53, September 2018, Pages 129-136


DOI: 10.1016/j.ejmp.2018.08.020

Purpose

To determine out-of-field doses produced in proton pencil beam scanning (PBS) therapy using Monte Carlo simulations and to estimate the associated risk of radiation-induced second cancer from a brain tumor treatment.


Methods

Simulations of out-of-field absorbed doses were performed with MCNP6 and benchmarked against measurements with tissue-equivalent proportional counters (TEPC) for three irradiation setups: two irradiations of a water phantom using proton energies of 78–147 MeV and 177–223 MeV, and one brain tumor irradiation of a whole-body phantom. Out-of-field absorbed and equivalent doses to organs in a whole-body phantom following a brain tumor treatment were subsequently simulated and used to estimate the risk of radiation-induced cancer. Additionally, the contribution of absorbed dose originating from radiation produced in the nozzle was calculated from simulations.


Results

Out-of-field absorbed doses to the TEPC ranged from 0.4 to 135 µGy/Gy. The average deviation between simulations and measurements of the water phantom irradiations was about 17%. The absorbed dose contribution from radiation produced in the nozzle ranged between 0 and 70% of the total dose; the contribution was however small in absolute terms. The absorbed and equivalent doses to the organs ranged between 0.2 and 60 µGy/Gy and 0.5–151 µSv/Gy. The estimated lifetime risk of radiation-induced second cancer was approximately 0.01%.


Conclusions

The agreement of out-of-field absorbed doses between measurements and simulations was good given the sources of uncertainties. Calculations of out-of-field organ doses following a brain tumor treatment indicated that proton PBS therapy of brain tumors is associated with a low risk of radiation-induced cancer.

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Repeat Stereotactic Radiosurgery for Progressive or Recurrent Vestibular Schwannomas

Christian Iorio-Morin, Roman Liscak, Vilibald Vladyka, Hideyuki Kano, Rachel C Jacobs, L Dade Lunsford, Or Cohen-Inbar, Jason Sheehan, Reem Emad, Khalid Abdel Karim, Amr El-Shehaby, Wael A Reda, Cheng-Chia Lee, Fu-Yuan Pai, Amparo Wolf, Douglas Kondziolka, Inga Grills, Kuei C Lee, David Mathieu

Neurosurgery, nyy416, 04 September 2018


DOI: 10.1093/neuros/nyy416

BACKGROUND

Stereotactic radiosurgery (SRS) is a highly effective management approach for patients with vestibular schwannomas (VS), with 10-yr control rates up 98%. When it fails, however, few data are available to guide management.


OBJECTIVE

To perform a retrospective analysis of patients who underwent 2 SRS procedures on the same VS to assess the safety and efficacy of this practice.


METHODS

This study was opened to centers of the International Gamma Knife Research Foundation (IGKRF). Data collected included patient characteristics, clinical symptoms at the time of SRS, radiosurgery dosimetric data, imaging response, clinical evolution, and survival. Actuarial analyses of tumor responses were performed.


RESULTS

Seventy-six patients from 8 IGKRF centers were identified. Median follow-up from the second SRS was 51.7 mo. Progression after the first SRS occurred at a median of 43 mo. Repeat SRS was performed using a median dose of 12 Gy. Actuarial tumor control rates at 2, 5, and 10 yr following the second SRS were 98.6%, 92.2%, and 92.2%, respectively. Useful hearing was present in 30%, 8%, and 5% of patients at first SRS, second SRS, and last follow-up, respectively. Seventy-five percent of patients reported stable or improved symptoms following the second SRS. Worsening of facial nerve function attributable to SRS occurred in 7% of cases. There were no reports of radionecrosis, radiation-associated edema requiring corticosteroids, radiation-related neoplasia, or death attributable to the repeat SRS procedure.


CONCLUSION

Patients with progressing VS after radiosurgery can be safely and effectively managed using a second SRS procedure.

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Interinstitutional patient transfers between rapid chemotherapy cycles were feasible to utilize proton beam therapy for pediatric Ewing sarcoma family of tumors

Interinstitutional patient transfers between rapid chemotherapy cycles were feasible to utilize proton beam therapy for pediatric Ewing sarcoma family of tumors | Radiosurgery and Radiotherapy | Scoop.it

Tomohei Nakao, Hiroko Fukushima, Takashi Fukushima, Ryoko Suzuki, Sho Hosaka, Yuni Yamaki, Chie Kobayashi, Atsushi Iwabuchi, Kazuo Imagawa, Aiko Sakai, Toko Shinkai, Kouji Masumoto, Shingo Sakashita, Tomohiko Masumoto, Masashi Mizumoto, Ryo Sumazaki, Hideyuki Sakurai


Reports of Practical Oncology & Radiotherapy, Volume 23, Issue 5, September–October 2018, Pages 442-450


DOI: 10.1016/j.rpor.2018.08.006

Aim

To assess the feasibility of transferring to the University of Tsukuba Hospital for proton beam therapy (PBT) during intensive chemotherapy in children with Ewing sarcoma family of tumors (ESFT) who had been diagnosed and started their first-line treatment at prefectural or regional centers for pediatric oncology.


Background

The treatment of ESFT relies on a multidisciplinary approach using intensive neoadjuvant and adjuvant chemotherapies with surgery and radiotherapy. Multi-agent chemotherapy comprising vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide (VDC-IE) is widely used for ESFT, and the interval between each course is very important for maintaining the intensity and effect of chemotherapy.


Materials and methods

Clinical information of patients who received PBT and VDC-IE between April 2009 and May 2016 was collected retrospectively. The intervals between each course of VDC-IE and adverse events were assessed.


Results


Fifteen patients were evaluated. No delays in the intervals of chemotherapy due to transfer were observed. There were no adverse events caused during/just after transfer and no increases in adverse events. The estimated 4-year overall and event-free survival rates were 94.6% and 84.8%, respectively.


Discussion

Although the results of efficacy are preliminary, survival rates were comparable with past studies. More experience and follow-up are required to further assess the efficacy of PBT for patients with ESFT.


Conclusion

Multidisciplinary therapy for children with ESFT involving transfer to our hospital for PBT during VDC-IE was feasible without treatment delay or an increase in adverse events.

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Moderately Hypofractionated Helical IMRT, FDG–PET/CT-guided, for Progressive Malignant Pleural Mesothelioma in Patients With Intact Lungs

Moderately Hypofractionated Helical IMRT, FDG–PET/CT-guided, for Progressive Malignant Pleural Mesothelioma in Patients With Intact Lungs | Radiosurgery and Radiotherapy | Scoop.it

Andrei Fodor, Sara Broggi, Elena Incerti, Italo Dell’Oca, Claudio Fiorino, Ana M. Samanes Gajate, Marcella Pasetti, Mauro G. Cattaneo, Paolo Passoni, Luigi Gianolli, Riccardo Calandrino, Maria Picchio, Nadia Di Muzio


Clinical Lung Cancer, 3 September 2018


DOI: 10.1016/j.cllc.2018.08.019

Introduction

The objective of this study was to present the outcomes of moderately hypofractionated helical intensity-modulated radiation therapy (HT) with/without simultaneous integrated boost (SIB) on fluorodeoxyglucose-positron emission tomography (FDG-PET) positive areas (gross tumor volume [GTV]-PET) for patients with progressive malignant pleural mesothelioma (MPM) after previous treatments.


Methods and Materials

From May 2006 to April 2014, 51 patients with a median age of 68.8 years (range, 38.6-82 years) were treated. There were 41 men and 10 women; 43 epithelioid MPM and 8 sarcomatoid, involving the left pleura in 25 patients and the right pleura in 26 patients. The initial stage was: I, 11 patients; II, 14 patients; III, 17 patients; and IV, 9 patients. Chemotherapy was prescribed for 46 patients, for 6 cycles (range, 0-18 cycles). Eighteen patients had pleurectomy/decortication, and 33 had talc pleurodesis. FDG-PET was used for target identification. A median dose of 56 Gy/25 fractions was prescribed to the involved pleura, and SIB to 62.5 Gy to GTV-PET was added in 38 patients.


Results

The median survival from diagnosis was 25.8 months (range, 8.4-99.0 months). One patient, treated with SIB, was alive at the October 2017 follow-up. Two cases of grade 5 radiation pneumonitis were registered. A GTV-PET ≤ 205 cc was predictive of late ≥ grade 2 lung toxicity, but also of better survival in stage III and IV disease: 5.9 versus 11.7 months (P = .04). A GTV-PET ≥ 473 cc was predictive of early death (P = .001).


Conclusions

Moderately hypofractionated, FDG-PET guided salvage HT in patients with progressive MPM after previous treatments showed acceptable toxicity and outcome results similar to adjuvant radiotherapy after pleurectomy/decortication, suggesting that the delay of radiotherapy is not detrimental to survival, and has the associated benefit of postponing inherent toxicity.

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Role of Stereotactic body radiation therapy in the management of oligometastatic renal cell carcinoma

Ciro Franzese, Davide Franceschini, Lucia Di Brina, Giuseppe Roberto D’Agostino, Pierina Navarria, Tiziana Comito, Pietro Mancosu, Stefano Tomatis, Marta Scorsetti


The Journal of Urology, 1 September 2018


DOI: 10.1016/j.juro.2018.08.049

Purpose

Kidney cancer has been increasing by 1.7% annually. Renal cell carcinoma (RCC) is the most common kidney cancer, and can metastasize. Our aim is to analyze patients treated with Stereotactic Body Radiation Therapy (SBRT) on metastases from RCC.


Methods

from 2004 to 2016, fifty-eight patients and 73 lesions were treated. Patients were candidate if maximum 3 metastases were diagnosed and primary tumour was resected. Toxicity was classified according to Common Terminology Criteria for Adverse Events (CTCAE) version 3.


Results

All the patients were affected by RCC, in particular clear cell type (82.7%). Thirty-nine (53.4%) metastases were located in the lungs and 19 (26%) were represented by lymph nodes. Less common bones (9.5%), liver (4.1%) and adrenal gland (6.8%). Median follow-up was 16.1 months (range 3.5 – 157.1). Rates of LC at 12- and 18- months were 90.2% and 90.2%. Rates of PFS at 12- and 18- months were 46.2% (95%CI 32.2% - 59%) and 35% (95%CI 21.4% - 48.9%). At univariate and multivariable analysis the presence of metachronous and single metastasis was predictive of better PFS. The use of systemic therapy before SBRT was predictive of improved local control in clear cell patients.


Conclusion

SBRT can be considered a safe approach and provides effective local control of oligometastatic RCC. However future prospective studies are necessary to evaluate its impact on survival and quality of life.

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Validation of Gean4 physics models for nuclear beams in extended media

Validation of Gean4 physics models for nuclear beams in extended media | Radiosurgery and Radiotherapy | Scoop.it

Junliang Chen, Sujun Yun, Tiekuang Dong, Zhongzhou Ren, Xiaoping Zhang


Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Volume 434, 1 November 2018, Pages 113-119


DOI: 10.1016/j.nimb.2018.08.022

The physical and biological processes induced by energetic heavy ions in extended media are of great importance for human space exploration and ion therapy. In this paper we check the validity of some nucleus-nucleus inelastic collision models in Geant4 for the transportation of heavy nuclei in materials. The depth-dose distributions of 12C and 56Fe beams in extended media and the yields of secondary fragments have been simulated by G4WilsonAbrasion model, G4BinaryLightIon model and G4QMD model. Then the propagation of heavy nuclei through materials used in space industry and the angular distributions of secondary neutrons are also simulated for further validation of the models. By comparing the simulated results with experimental data, it is found that the G4QMD model gives the best results. The implication for estimating the radiation environment on Mars caused by GCRs is also discussed.

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Clinical perineural invasion of cutaneous head and neck cancer: Impact of radiotherapy, imaging, and nerve growth factor receptors on symptom control and prognosis

Clinical perineural invasion of cutaneous head and neck cancer: Impact of radiotherapy, imaging, and nerve growth factor receptors on symptom control and prognosis | Radiosurgery and Radiotherapy | Scoop.it

Jie Jane Chen, Jeremy P. Harris, Christina S. Kong, John B. Sunwoo, Vasu Divi, Kathleen C. Horst, Sumaira Z. Aasi, S. TylerHollmig, Wendy Y. Har


Oral Oncology, Volume 85, October 2018, Pages 60-67


DOI: 10.1016/j.oraloncology.2018.08.014

Objectives

Clinical perineural invasion (CPNI) of cutaneous head and neck cancer is associated with poor prognosis and presents a therapeutic dilemma. The purpose of this study was to determine the relationship between CPNI and nerve growth factor receptors (NGFR), and the impact of radiotherapy (RT), imaging, and NGFR on symptom control and disease-related outcomes.


Materials and methods

We retrospectively reviewed patients with CPNI of cutaneous head and neck cancer who were treated with RT between 2010 and 2015 at our institution. Exact chi-square and Wilcoxon rank-sum tests compared patients with positive versus negative staining for TrkA and/or CD271. Gray’s test determined differences in cumulative incidences of 1- and 2-year locoregional recurrence (LRR) and cancer-specific mortality (CSM).


Results

Twenty-three patients had a median overall follow-up of 31.4 months from initial clinical symptoms and 19.7 months from pathological confirmation of PNI. The most prevalent symptoms were numbness (70%) and pain (57%). Sixteen patients (70%) experienced symptom improvement or control, especially decreased pain (85%), within a median of 2.6 months from starting RT. The 1- and 2-year rates of overall LRR were 37% and 71%, while those of overall CSM were 11% and 25%, respectively. Patients who stained positively for TrkA and/or CD271 had significantly worse LRR compared to patients who stained negatively for both markers (p = 0.046).


Conclusion

Positive TrkA and/or CD271 staining predicts worse outcomes. Patients may benefit from aggressive RT for local control and symptom improvement. Future research is needed to identify the potential for anti-nerve growth factor therapies in CPNI.

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Surgery, radiotherapy or a combined modality for jugulotympanic paraganglioma of Fisch class C and D

T.T.G. Jansen, J.H.A.M. Kaanders, G. N. Beute, H.J.L.M. Timmers, H.A.M. Marres, H.P.M. Kunst


Clinical Otolaryngology, 30 August 2018


DOI: 10.1111/coa.13216

Objectives

To identify the risks associated with surgery, radiotherapy or a combined treatment approach for Fisch class C and D jugulotympanic paraganglioma, in order to develop an individualized approach for each patient depending on Fisch class, age, mutation presence, tumor size growth rate and presenting symptoms


Design

A retrospective multicenter cohort study with all patient records of patients with a head and neck paraganglioma in the Radboudumc, Nijmegen and the St. Elisabeth Hospital, Tilburg, the Netherlands.
Main outcome measures local control, cranial nerve damage, complications, function recovery.


Results

We found highest local control rates after tumor debulking with postoperative radiotherapy in case of residual tumor growth, referred to as the combined treatment group, (100%; n = 19), which was significantly higher than the surgical group (82%; n = 17; p = 0.00), but did not differ from the radiotherapy group (90%; n = 29). There were significantly less complications in the radiotherapy group, when compared to surgery (63 vs. 27%; p = 0.002) and the combined group (44 vs. 27%; p = 0.016). Furthermore, using a logistic regression model, we found that pre‐treatment tumor growth was a negative predictor for post treatment cranial nerve function recovery (OR = 50.178, p = 0.001), reducing the chance of symptom recovery (67.3% versus 35.7%) post‐treatment.


Conclusions

Radiotherapy should be the treatment of choice for the elderly. For younger patients tumor debulking should be considered, with potential radiotherapy in case of residual tumor growth.

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Low-Dose Gamma Knife Radiosurgery for Acromegaly

Low-Dose Gamma Knife Radiosurgery for Acromegaly | Radiosurgery and Radiotherapy | Scoop.it
Fu-Yuan Pai, Ching-Jen Chen, Wen-Hsin Wang, Huai-Che Yang, Chung Jung Lin, Hsiu-Mei Wu, Yi-Chun Lin, Harn-Shen Chen, Yu-Shu Yen, Wen-Yuh Chung, Wan-Yuo Guo, David Hung-Chi Pan, Cheng-Ying Shiau, Cheng-Chia Lee

Neurosurgery, nyy410, 29 August 2018


DOI: 10.1093/neuros/nyy410

Background

Remission rate is associated with higher dose of Gamma Knife Radiosurgery (GKRS; Gamma Knife: Elekta AB, Stockholm, Sweden) for acromegaly, but the dose ≥25 Gy is not always feasible when the functioning adenoma is close to optic apparatus


Objective

To evaluate the efficacy and safety of low-dose (<25 Gy) GKRS in the treatment of patients with acromegaly.


Methods

Single-center retrospective review of acromegaly cases treated with GKRS between June 1994 and December 2016. A total of 76 patients with the diagnosis of acromegaly who were treated with low-dose GKRS were selected for inclusion. Patients were treated with a median margin dose, isodose line, and treatment volume of 15.8 Gy, 57.5%, and 4.8 mL, respectively. Any identifiable portion of the optic apparatus was limited to a radiation dose of 10 Gy. All patients underwent full endocrine, ophthalmological, and imaging evaluation prior to and after GKRS treatments, and results of these were analyzed.


Results

Biochemical remission was achieved in 33 (43.4%) patients. Actuarial remission rates were 20.3%, 49.9%, and 76.3% at 4, 8, and 12 yr, respectively. Absence of cavernous sinus invasion (P = .042) and lower baseline insulin-like growth factor-1 levels (P = .019) were significant predictors of remission. New hormone deficiencies were found in 9 (11.8%) patients. Actuarial hormone deficiency rates were 3%, 14%, and 22.2% at 4, 8, and 10 yr, respectively. Two (2.6%) patients who achieved initial remission experienced recurrence. No optic complications were encountered.


CONCLUSION

Reasonable remission and new hormone deficiency rates can be achieved with low-dose GKRS for acromegaly. These rates may be comparable to those with standard GKRS margin doses.

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Organ at risk dose measurements following radiotherapy treatment for breast cancer patients

Ibrahim Duhaini, Nour Hodroj, Fatimah Farhat, Saad Ayoubi, Ahmad Maarouf, Mahmoud Korek


Health and Technology, pp 1–6, 29 August 2018


DOI:10.1007/s12553-018-0254-2


Radiotherapy technologies are one of the most common treatments for cancer, they have been successfully used to damage cancer cells, with as little harm as possible to nearby healthy cells, however Secondary cancer risk following radiotherapy is an increasingly important topic in clinical oncology with impact on treatment decision making and on patient management. The objective of this study is to measure the skin radiation dose received by the treated breast as well as the dose to the lungs in cancer patients undergoing breast radiotherapy and estimate the probability for radiation-induced cancer, i.e. secondary cancer and the probability of lung cancer. Usage of RANDO phantoms and GafChromic dosimetry films to do dose measurements during breast radiotherapy. Measured dose and calculated organ dose from patients were compared. The calculated doses were done using the effective dose formula. Measured point doses of both lungs were compared to those calculated by TPS (treatment planning system). Relative Risk (RR) and Probability of Causation (PC) of lungs- probability of cancer- were calculated from patient’s mean doses to the organs (right lung and left lung) using the model described in BEIR V report. RR mean values were 1.278 and 1.032 for ipsilateral and contralateral lungs respectively. In addition, PC mean values were 20.93 % and 3.099% for ipsilateral and contralateral lungs respectively. Breast cancer patients are susceptible to an increased risk of secondary cancer of ipsilateral lungs more than in the contralateral ones.

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Stereotactic Body Radiotherapy for Spinal Metastases at the Extreme Ends of the Spine: Imaging-Based Outcomes for Cervical and Sacral Metastases

Stereotactic Body Radiotherapy for Spinal Metastases at the Extreme Ends of the Spine: Imaging-Based Outcomes for Cervical and Sacral Metastases | Radiosurgery and Radiotherapy | Scoop.it
K Liang Zeng, Sten Myrehaug, Hany Soliman, Chia-Lin Tseng, Eshetu G Atenafu, Mikki Campbell, Salman Faruqi, Young K Lee,  Mark Ruschin, Leodante da Costa, Victor Yang, Julian Spears, Chris Heyn, Pejman Jabehdar Maralani, Cari Whyne, Albert Yee, Arjun Sahgal

Neurosurgery, nyy393, 29 August 2018


DOI: 10.1093/neuros/nyy393

Background

The unique anatomy and biomechanical features of the cervical spine and sacrum may impact treatment outcomes following spine stereotactic body radiotherapy (SBRT). Current data for spine metastases are not specific for these locations.


Objective

To report imaging-based SBRT outcomes to cervical and sacral metastases.


Methods

We retrospectively reviewed our prospective spine SBRT database for cervical and sacral metastases. Patients were followed at 2- to 3-mo intervals with a clinical visit and full spine magnetic resonance imaging (MRI) and we report overall survival (OS), vertebral compression fracture (VCF), and MR imaging-based local control (LC) rates.


Results

Fifty-two patients and 93 treated spinal segments were identified. Fifty-six segments were within the cervical spine and 37 within the sacrum, the median follow-up was 14.4 and 19.5 mo, and the median total dose/number of fractions was 24 Gy/2, respectively. Cumulative LC at 1 and 2 yr were 94.5% and 92.7% for the cervical cohort, and 86.5% and 78.7% in the sacral cohort, respectively. Lack of posterior spinal element involvement in the cervical spine (P < .0001) and absence of epidural disease (hazard ratio 0.275, 95% confidence interval 0.076-0.989, P = .048) in the sacral cohort predicted LC. Median OS was 16.3 and 28.5 mo in the cervical spine and sacrum cohorts, respectively. Two cases of sacral VCF, 1 brachial plexopathy, and 1 lumbar-sacral plexopathy were observed.


CONCLUSION

Although high rates of LC were observed, strategies specific to the sacrum may require further optimization.

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