ONCOmmunity

Selenium supplementation and prostate cancer mortality.

By: Stacey A Kenfield, Erin L Van Blarigan, Natalie DuPre, Meir J Stampfer, Edward L Giovannucci, June M Chan

Department of Urology, University of California, San Francisco, San Francisco, CA (ELVB, SAK, JMC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SAK, ND, MJS, EG); Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA (ELVB, JMC); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (MJS, EG); Department of Nutrition, Harvard School of Public Health, Boston, MA (MJS, EG). KenfieldS@urology.ucsf.edu.
2015-1-; doi: 10.1093/jnci/dju360

Abstract

Background

Few studies have evaluated the relation between selenium supplementation after diagnosis and prostate cancer outcomes.

Methods

We prospectively followed 4459 men initially diagnosed with nonmetastatic prostate cancer in the Health Professionals Follow-Up Study from 1988 through 2010 and examined whether selenium supplement use (from selenium-specific supplements and multivitamins) after diagnosis was associated with risk of biochemical recurrence, prostate cancer mortality, and, secondarily, cardiovascular disease mortality and overall mortality, using Cox proportional hazards models. All P values were from two-sided tests.

Results

We documented 965 deaths, 226 (23.4%) because of prostate cancer and 267 (27.7%) because of cardiovascular disease, during a median follow-up of 8.9 years. In the biochemical recurrence analysis, we documented 762 recurrences during a median follow-up of 7.8 years. Crude rates per 1000 person-years for prostate cancer death were 5.6 among selenium nonusers and 10.5 among men who consumed 140 or more μg/day. Crude rates per 1000 person-years were 28.2 vs 23.5 for all-cause mortality and 28.4 vs 29.3 for biochemical recurrence, for nonuse vs highest-dose categories, respectively. In multivariable analyses, men who consumed 1 to 24 μg/day, 25 to 139 μg/day, and 140 or more μg/day of supplemental selenium had a 1.18 (95% confidence interval [CI] = 0.73 to 1.91), 1.33 (95% CI = 0.77 to 2.30), and 2.60-fold (95% CI = 1.44 to 4.70) greater risk of prostate cancer mortality compared with nonusers, respectively, P trend = .001. There was no statistically significant association between selenium supplement use and biochemical recurrence, cardiovascular disease mortality, or overall mortality.

Conclusion

Selenium supplementation of 140 or more μg/day after diagnosis of nonmetastatic prostate cancer may increase risk of prostate cancer mortality. Caution is warranted regarding usage of such supplements among men with prostate cancer.