Selenium has been suggested to have preventative effects against lung cancer. In a recent clinical trial, patients with stage I non-small cell lung cancer (NSCLC) that had been completely surgically removed were given either selenium supplements or a placebo for 2 years after surgery. Interim results showed that patients receiving selenium were no less likely to have their lung cancer return than those given a placebo. Because there were hints that selenium-treated patients may be indeed more likely to develop new tumors, the study was halted. Final analyses show no harm from taking selenium, but no protection against lung cancer either.