Posted: November 11, 2013

Selenium supplementation in the diet has been touted as a way to prevent cancer for years.  Some recent data suggest that this strategy has promise only in areas of endemic selenium deficiency.  See the recent post in StarkOncology for details.  Now comes a very important study trying to assess whether Selenium supplementation can prevent a second lung cancer in people who have already had their first lung cancer.   In the November 20 issue of the Journal of Clinical Oncology (click here for the abstract; email Dr. Stark for the full article) Dan Karp and Gerald Klamon among others report on a randomized prospective trial in which half of the lung cancer patients recently treated for Stage I lung cancer (with a high likelihood of cure) were given Selenium and the other half placebo.  The dose and formulation of Selenium were as previously administered in positive trials — as Seleno-methionine at a dose of 200 mcg/day.   Over 1500 patients were enrolled.  At the time of final data analysis there was no evidence that Selenium supplementation had any beneficial effect.  In an accompanying editorial Dubinett from UCLA raised important issues, such as the impact of endemic Selenium deficiency on its ability to protect patients from a second lung cancer (not addressed in the study) and the possibility that with genetic analysis of the lung tumors a subset of patients could be identified who might benefit from this approach,  as opposed to the group in general, where no benefit was seen.  Dr. Stark weighs in: “This study is one more nail in the coffin of Selenium as a cancer preventative.   Just because something should work doesn’t mean it will.  Would it were so, but it’s not. “