Roswell Park Cancer Institute, Buffalo, New York.Southwest Oncology Group Statistical Center, Seattle, Washington; Wayne State University, Detroit; University of Michigan, Ann Arbor, Michigan; Dana-Farber Cancer Institute; Cancer and Leukemia Group B, MAVERIC Cooperative Studies Program Coordinating Center, VA Boston Healthcare System, and Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts; Cleveland Clinic, Cleveland, Ohio; MD Anderson Cancer Center, Houston, Texas; National Cancer Institute, Division of Cancer Prevention, Bethesda, Maryland; Arizona Cancer Center, Tucson, Arizona; University of Wisconsin, Madison, Wisconsin; Eastern Cooperative Oncology Group, Duke University School of Medicine, Durham, North Carolina; University of Colorado Health Sciences Center, Aurora, Colorado; and University of Texas Health Science Center, San Antonio, Texas.
The threat of prostate cancer and the significant and often negative impact of its treatment underscore the importance of prevention. High-grade prostatic intraepithelial neoplasia (HGPIN) has been identified as a potential premalignant lesion marking an increased risk of prostate cancer and substantial evidence suggests that men with HGPIN are in need of prostate cancer prevention. In vitro, in vivo, epidemiologic, and clinical trial evidence that selenium supplementation protects against prostate cancer motivated the study we report here: a double-blind, randomized, placebo-controlled trial of selenium 200 (μg/d) as selenomethionine in men with HGPIN. The primary endpoint was progression of HGPIN to prostate cancer over a 3-year period. This National Cancer Institute Intergroup trial was coordinated by the Southwest Oncology Group (SWOG). Of 619 enrolled patients, 423 randomized men with HGPIN (212 selenium and 211 placebo) were eligible (by central pathology review) and included in the primary analysis. Three-year cancer rates were 36.6% (placebo) versus 35.6% (selenium; P = 0.73, adjusted). The majority of patients who developed cancer on trial (70.8%, selenium and 75.5%, placebo) had a Gleason score of 6 or less than 6; there were no differences in Gleason scores between the two arms. Subset analyses included the finding of a nonsignificantly reduced prostate cancer risk (relative risk = 0.82; 95% CI: 0.40-1.69) in selenium versus placebo patients in the lowest quartile of baseline plasma selenium level (< 106 ng/mL). Overall, and in all other subsets defined by baseline blood selenium levels, selenium supplementation had no effect on prostate cancer risk. The 36% prostate cancer rate in men with HGPIN indicates the association of this lesion with an elevated prostate cancer risk. Future study in this setting should focus on selenium-deficient populations and selenium pharmacogenetics.
Marshall JR, Tangen CM, Sakr WA, Wood DP Jr, Berry DL, Klein EA, Lippman SM, Parnes HL, Alberts DS, Jarrard DF, Lee WR, Gaziano JM, Crawford ED, Ely B, Ray M, Davis W, Minasian LM, Thompson IM Jr. Are you the author?
Reference: Cancer Prev Res (Phila). 2011 Sep 6. Epub ahead of print.