Selenium, a supplement taken by people hoping to ward off cancer and other diseases, has proven to be of no benefit in reducing a patient’s risk of developing lung cancer—either a recurrence or second primary malignancy. The [removed]findings[/removed] of the international Phase III clinical trial were presented at the American Society of Clinical Oncology 2010 Annual Meeting.
From 2000 to 2009, the trial enrolled 1,522 Stage I non-small cell lung cancer patients, all of who had their tumors surgically removed and were cancer-free for at least 6 months post-surgery. Participants were randomized to receive either 200 micrograms of selenium or placebo. The study’s primary endpoints were reduction of development of a new cancer, or second primary, and/or recurrence of their initial cancer.
The study was halted early, however, after an interim analysis revealed that the progression-free survival was superior in the placebo arm—78% taking the placebo were alive without recurrence after 5 years, compared to 72% on selenium. A total of 216 secondary primary tumors developed, of which 84 (38.9%) were lung cancers. Of those taking selenium, 1.9% developed a secondary primary tumor after the first year, compared to 1.4% taking placebo. In total, 3.66% of participants in the selenium arm developed a secondary primary tumor of any type after 1 year, compared to 4.1% in the placebo group.
Side effects were minimal and no different in both groups. Of those taking placebo, 38% had grade 1 or 2 toxicity, and 3% had grade 3, compared to 39% and 1%, respectively in those taking the supplement.
The study was stopped by the independent Data and Safety Monitoring Committee due to futility.
The researchers did find that in a small group of the lung cancer patients who were never smoked, selenium did provide a small benefit; however, the size of the group of patients, 94, was too small to be statistically significant.