ASCO 2010: No prevention benefit of selenium for secondary tumours in non-small cell lung cancer

5 Jun 2010

A Phase III study of patients treated for early-stage, non-small cell lung cancer (NSCLC) finds that selenium is not effective for preventing a second primary lung cancer from developing.

"There had been strong suggestive evidence that selenium could decrease the risk of a second primary lung tumour," said Daniel Karp, MD, professor of thoracic/head and neck medical oncology at the University of Texas M.D. Anderson Cancer Center in Houston. "Unfortunately, we couldn't find any
evidence that it was any more effective in doing so than a placebo. Based on the data, we cannot recommend that patients with lung cancer take selenium to prevent a second primary tumour."

NSCLC patients with resectable (stage I) lung cancer can be treated effectively with surgery more than 80 percent of the time Approximately 1 to 2 percent of early-stage NSCLC patients develop a second primary cancer in the first year after surgery, and the chance of developing another new lung cancer rises by approximately 2 percent each year. Previous studies, including a large skin cancer trial reported in 1996, indicated some potential preventive effects of selenium against lung cancer.

In this randomized, double-blind intergroup study led by the Eastern Cooperative Oncology Group and conducted between 2000 and 2009, 1,522 patients with stage IA and IB NSCLC that had been surgically removed were randomly assigned to receive selenium (200 micrograms daily) or a placebo for four years.

Patients had to be cancer-free for at least six months after surgery to participate. Twice as many participants received selenium as placebo. The study was halted early – after a more than four-year median follow-up – when it was found that the five-year progression-free survival (the chance of developing a new cancer or recurrence) was 78 percent among the participants taking placebo compared to 72 percent among patients receiving selenium. In total, 216 patients developed second primary cancer, including 84 (38.9 percent) lung cancer tumours. The researchers found that about 1.9 percent of those in the selenium group developed a second primary lung tumour after one year, compared to 1.4 percent taking placebo. Overall, approximately 4.1 percent of participants who took selenium developed a second primary tumour of any type after one year, compared to 3.66 percent in the placebo group. Side effects were minimal.

Source: ASCO