Discussion
cancer, prostate cancer, NMIBC
CANCER, RECURRENCE, PROSTATE CANCER
We observed no benefit of selenium for recurrence, progression, or overall survival in patients with NMIBC. We observed an association between vitamin E supplementation and an increased risk of recurrence but no association with progression or overall survival. The assumptions of the factorial trial design were demonstrated to be correct. The randomization used contemporary risk categorization as a stratification factor; over time, risk categorization has changed.SELENIB is, to our knowledge, the first trial to investigate the use of selenium and vitamin E for preventing recurrence and progression in patients newly diagnosed with NMIBC. In 2011, the Selenium and Vitamin E Cancer Prevention Trial (SELECT) concluded that dietary supplementation with vitamin E (400 IU/d all-rac-α-tocopheryl acetate) significantly increased the risk of prostate cancer among healthy menTrials of dietary supplements in cancer prevention are important, as demonstrated here. Our data show no evidence of benefit from selenium and evidence of harm from vitamin E—a compound readily available over the counter. Future micronutrient and/or vitamin chemoprevention studies in NMIBC should carefully consider choice of compound, underlying biology, preclinical evidence, and study design.