Selenium and Vitamin E Cancer Prevention Trial

The Selenium and Vitamin E Cancer Prevention Trial, or SELECT, was a clinical trial conducted with the goal of determining whether vitamin E and selenium supplements could prevent prostate cancer.[1] Enrollment for the trial began in 2001 and ended in 2004.[1] It cost approximately $114 million to conduct and was performed at over 400 different research centers.[2] It was primarily funded by the National Cancer Institute (NCI) and was carried out by SWOG.[1] It was stopped early because the supplements did not show any benefit in preventing prostate cancer. Subsequent research based on the trial has generally found that selenium and vitamin E do not prevent prostate cancer.

Methodology

The study followed over 35,000 men in the United States, Puerto Rico, and Canada, who were assigned randomly to receive either both a selenium and vitamin E supplement, selenium and placebo, vitamin E and placebo, or two placebos.[3] It was one of the largest cancer prevention trials ever conducted,[4] and was described by the NCI as "the largest-ever prostate cancer prevention study."[5] The study was originally planned to last for twelve years after enrollment began.[6] However, it was stopped early in 2008 because no protective effect of supplementation on prostate cancer risk was found, and because the results suggested that vitamin E might increase the risk.[1] About 17,000 participants from the original SELECT completed an additional four years of a Centralized Follow-Up from 2010 until May 31, 2014, when SELECT closed.[7] The follow-up involved sending questionnaires to participants annually, which they could also fill out online.[1]

Results

Initial results were published in 2008 in JAMA.[8] The initial results found that the increase in risk associated with Vitamin E was "statistically nonsignificant",[8] which the researchers wanted to verify in a subsequent study.[9]

A subsequent 2010 study further described SELECT's results and found that neither selenium nor vitamin E, on their own or in combination, prevented prostate cancer.[10]

A 2011 study based on the trial found that the risk of prostate cancer was elevated by 17% in the group that took vitamin E supplements, which was statistically significant.[6][11]

A 2014 study based on SELECT data found that selenium supplementation increased the risk of high-grade prostate cancer in men who had a higher baseline selenium status.[12][13]

A 2014 Cochrane review found that SELECT raised concerns about a possible association between selenium supplements and an increase in risk of type 2 diabetes, alopecia and dermatitis. The review concluded that "no convincing evidence suggests that selenium supplements can prevent cancer in humans."[14]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Selenium and Vitamin E Cancer Prevention Trial Q&A
  2. ↑ Simon, Harvey B. (17 September 2009). "Do Vitamins Prevent Prostate Cancer?". Chicago Tribune. Retrieved 17 November 2014.
  3. ↑ Neighmond, Patti (27 October 2008). "Study: Vitamin E Doesn't Prevent Prostate Cancer". NPR. Retrieved 17 November 2014.
  4. ↑ Hatfield, DL; Gladyshev, VN (February 2009). "The Outcome of Selenium and Vitamin E Cancer Prevention Trial (SELECT) reveals the need for better understanding of selenium biology.". Molecular interventions 9 (1): 18–21. doi:10.1124/mi.9.1.6. PMID 19299660.
  5. ↑ Largest-Ever Prostate Cancer Prevention Trial Opens: 32,000 Men Sought to Test Vitamin E and Selenium
  6. ↑ 6.0 6.1 "Selenium, vitamin E supplements may up prostate cancer risk". UPI. 21 February 2014. Retrieved 17 November 2014.
  7. ↑ SELECT
  8. ↑ 8.0 8.1 Lippman, Scott M.; Klein, Eric A.; Goodman, Phyllis J.; Lucia, M. Scott; Thompson, Ian M.; Ford, Leslie G.; Parnes, Howard L.; Minasian, Lori M.; Gaziano, J. Michael; Hartline, Jo Ann; Parsons, J. Kellogg; Bearden, James D.; Crawford, E. David; Goodman, Gary E.; Claudio, Jaime; Winquist, Eric; Cook, Elise D.; Karp, Daniel D.; Walther, Philip; Lieber, Michael M.; Kristal, Alan R.; Darke, Amy K.; Arnold, Kathryn B.; Ganz, Patricia A.; Santella, Regina M.; Albanes, Demetrius; Taylor, Philip R.; Probstfield, Jeffrey L.; Jagpal, T. J.; Crowley, John J.; Meyskens, Frank L.; Baker, Laurence H.; Coltman, Charles A. (7 January 2009). "Effect of Selenium and Vitamin E on Risk of Prostate Cancer and Other Cancers". JAMA 301 (1): 39–51. doi:10.1001/jama.2008.864. PMID 19066370.
  9. ↑ Jaslow, Ryan (5 August 2013). "Too much vitamin E tied to prostate cancer risk". CBS News. Retrieved 17 November 2014.
  10. ↑ Dunn, BK; Richmond, ES; Minasian, LM; Ryan, AM; Ford, LG (2010). "A nutrient approach to prostate cancer prevention: The Selenium and Vitamin E Cancer Prevention Trial (SELECT).". Nutrition and cancer 62 (7): 896–918. doi:10.1080/01635581.2010.509833. PMID 20924966.
  11. ↑ Klein, Eric A.; Thompson, Ian M.; Tangen, Catherine M.; Crowley, John J.; Lucia, M. Scott; Goodman, Phyllis J.; Minasian, Lori M.; Ford, Leslie G.; Parnes, Howard L.; Gaziano, J. Michael; Karp, Daniel D.; Lieber, Michael M.; Walther, Philip J.; Klotz, Laurence; Parsons, J. Kellogg; Chin, Joseph L.; Darke, Amy K.; Lippman, Scott M.; Goodman, Gary E.; Meyskens, Frank L.; Baker, Laurence H. (12 October 2011). "Vitamin E and the Risk of Prostate Cancer". JAMA 306 (14): 1549–56. doi:10.1001/jama.2011.1437. PMID 21990298.
  12. ↑ Kristal, A. R.; Darke, A. K.; Morris, J. S.; Tangen, C. M.; Goodman, P. J.; Thompson, I. M.; Meyskens, F. L.; Goodman, G. E.; Minasian, L. M.; Parnes, H. L.; Lippman, S. M.; Klein, E. A. (22 February 2014). "Baseline Selenium Status and Effects of Selenium and Vitamin E Supplementation on Prostate Cancer Risk". JNCI Journal of the National Cancer Institute 106 (3): djt456–djt456. doi:10.1093/jnci/djt456.
  13. ↑ Press Association (21 February 2014). "Some vitamin supplements raise risk of cancer in men, research shows". The Guardian. Retrieved 17 November 2014.
  14. ↑ Vinceti, M; Dennert, G; Crespi, CM; Zwahlen, M; Brinkman, M; Zeegers, MP; Horneber, M; D'Amico, R; Del Giovane, C (30 March 2014). "Selenium for preventing cancer". The Cochrane database of systematic reviews 3: CD005195. doi:10.1002/14651858.CD005195.pub3. PMID 24683040.
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