Oral Selenium Supplementation Has No Effect on Prostate-Specific Antigen Velocity in Men Undergoing Active Surveillance for Localized Prostate Cancer
What this study found
Selenium did not slow prostate cancer progression as measured by PSA velocity. Compared with placebo, PSA velocity differences were not significant for 200 μg/day (-0.03, 95% CI -0.09 to 0.03; P = 0.32) or 800 μg/day (-0.02, 95% CI -0.08 to 0.04; P = 0.61). In quartile analyses, the 800 μg/day group showed a higher PSA velocity than placebo in the highest baseline selenium quartile (P = 0.018), while lower quartiles were not significantly different. Time to treatment was also not significantly different by Kaplan-Meier estimates, supporting the conclusion that selenium supplementation did…
- Study & population
- Randomized, placebo-controlled multicenter trial in men with biopsy-proven localized, nonmetastatic prostate cancer who chose active surveillance rather than immediate treatment.
- Intervention
- Men on active surveillance received oral selenized yeast at either 200 μg/day or 800 μg/day, taken daily for up to 5 years, compared with placebo.
- Key limitation
- The active intervention arms were small, with 47 participants randomized per dose, limiting power for subgroup and adverse event analyses.
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Open PDFOriginal abstract
The Nutritional Prevention of Cancer trial showed a 52% lower incidence of prostate cancer in men supplemented with selenium. As a result, our study was designed to assess whether selenium supplementation attenuates the progression of prostate cancer. A phase 2 randomized, double-blind, placebo-controlled clinical trial was conducted in men with localized nonmetastatic prostate cancer who had elected to forgo active treatment and be followed by active surveillance. A total of 140 men were randomized to placebo (n = 46), 200 μg/d (n = 47), or 800 μg/d (n = 47) selenium p.o. (as selenized yeast) and followed every 3 months for up to 5 years. Prostate-specific antigen (PSA) velocity was used as a marker of prostate cancer progression and was estimated using mixed-effects regression. Adjusting for age, body mass index, baseline selenium, smoking, baseline PSA, race, PSA method, and Gleason score, PSA velocities for the 200 μg/d and 800 μg/d treatment groups were not statistically significantly different from placebo (P = 0.32 and P = 0.61, respectively). In the highest quartile of baseline selenium, men supplemented with 800 μg selenium showed statistically significantly higher PSA velocity as compared with placebo (P = 0.018). Selenium supplementation did not show a protective effect on PSA velocity in subjects with localized prostate cancer. On the contrary, supplementation with high-dose selenium was observed to be a risk factor for increased PSA velocity in men with high baseline plasma selenium concentrations. Cancer Prev Res; 3(8); 1035–43. ©2010 AACR.