Deaths from lung cancer have been decreasing across the U.S., contributing to an overall trend of falling cancer death rates, according to a report coauthored by several major medical and research institutions. Covering the period from 1975 to 2010, the report finds that the decrease in lung cancer deaths has accelerated in recent years. The rate of new lung cancer cases has also fallen, though to a lesser extent. Much of this trend is likely due to the significant reduction in tobacco smoking in past decades, which is producing a delayed effect. The report also showed that the presence of additional illnesses aside from cancer, which can greatly affect outcomes in some other cancer types, has less of an effect on prognosis in lung cancer.