Selenium (Se) has been reported to have possible lung cancer chemopreventive benefits based on a large skin cancer trial secondary observation. (JAMA 1996; 276: 1957-1963). Since that time, research continued to suggest that selenium could decrease risk of second primary tumor (SPT) in persons with resected NSCLC. In 2007, a publication from another group suggested an increased association of selenium with T2DM (Annals Int Med 147:217-223).

However, data of a Phase III study of patients treated for early-stage, non-small cell lung cancer (NSCLC) presented at the 46th Annual Meeting of the American Society of Clinical Oncology (ASCO) being held from June 4 – 8 in Chicago, IIllinois (USA), finds that selenium is not effective for preventing a second primary lung cancer from developing.

Suggestive evidence
?There had been strong suggestive evidence that selenium could decrease the risk of a second primary lung tumor,? 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 tumor.?

NSCLC patients with resectable (stage I) lung cancer can be treated effectively with surgery more than 80% of the time Approximately 1 to 2 % 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% each year.

Previous studies, including a large skin cancer trial reported in 1996, indicated some potential preventive effects of selenium against lung cancer.

ECOG-trial
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% among the participants taking placebo compared to 72% among patients receiving selenium. In total, 216 patients developed second primary cancer, including 84 (38.9%) lung cancer tumors.

The researchers found that about 1.9% of those in the selenium group developed a second primary lung tumor after one year, compared to 1.4% taking placebo. Overall, approximately 4.1% of participants who took selenium developed a second primary tumor of any type after one year, compared to 3.66% in the placebo group.

Side effects were minimal. No increase in diabetes mellitus or skin cancer was detected. Selenium was safe but conferred no benefit over placebo. Methylation studies are continuing.

Oral Abstract Session: Lung Cancer
Lead author: Daniel Karp, MD, The University of Texas, M. D. Anderson Cancer Center Houston, TX
Date: Saturday, June 5, 2010, 4:15-4:30 PM CDT
Location: E Hall D1
Abstract: CRA 7004
Title: A phase III intergroup randomized double blind chemoprevention trial of selenium (Se) supplementation in resected stage I non small cell lung cancer (NSCLC).
Authors: D. D. Karp, S. J. Lee, G. L. Shaw Wright, D. H. Johnson, M. R. Johnston, G. E. Goodman, G. H. Clamon, G. S. Okawara, R. Marks, J. C. Ruckdeschel, MDACC Thoracic Chemoprevention Research Group.