The modulation of prostate cancer risk with alpha-tocopherol: a pilot randomized, controlled clinical trial.
OBJECTIVE
Studies suggest that vitamin E may decrease the risk of prostate cancer. The Prevention Research Veteran Affairs E-vitamin Nutrition Trial is a randomized, double-blind, placebo controlled study designed to assess the effects of vitamin E supplementation on biomarkers associated with prostate cancer risk in peripheral blood and prostate tissue.


METHODS
A total of 44 patients with increased prostate specific antigen (PSA) and/or abnormal digital rectal examination on initial evaluation were randomized to receive 400 IU vitamin E (22) vs placebo (22). Serum vitamin E, PSA, dehydroepiandrosterone, testosterone and insulin-like growth factor-1 (IGF-1) were measured in the 2 groups at baseline and then at 3-month intervals. Results are reported in 28 patients (placebo in 14 and vitamin E in 14) who completed the treatment as specified by the protocol.


RESULTS
Serum Vitamin E was significantly higher in patients on vitamin E supplementation. alpha-Tocopherol supplementation did not affect the levels of PSA, serum androgens (testosterone and dehydroepiandrosterone) or (IGF-1).


CONCLUSIONS
Serum alpha-tocopherol is increased by oral supplementation of vitamin E. We found that alpha-tocopherol supplementation has no effect on serum androgens, IGF-1 or PSA. The lack of an effect of vitamin supplementation on PSA avoids any bias in the diagnosis of prostate cancer in vitamin E treated patients. Our results suggest that a decrease in prostate cancer risk with alpha-tocopherol is likely to occur through a mechanism that is nonhormonal and independent of IGF-1.
Hernáandez
Javier
J
Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA.
Syed
Samira
S
Weiss
Geoffrey
G
Fernandes
Gabriel
G
von Merveldt
Dendra
D
Troyer
Dean A
DA
Basler
Joseph W
JW
Thompson
Ian M
IM
D000975:Antioxidants / Q000378:metabolism; D003687:Dehydroepiandrosterone / Q000097:blood; D019587:Dietary Supplements; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000517:prevention & control*; D013739:Testosterone / Q000097:blood; D014810:Vitamin E / Q000627:therapeutic use*; D024502:alpha-Tocopherol / Q000097:blood
D000975:Antioxidants; D014810:Vitamin E; D013739:Testosterone; D003687:Dehydroepiandrosterone; D007334:Insulin-Like Growth Factor I; D017430:Prostate-Specific Antigen; D024502:alpha-Tocopherol