TY - JOUR
T1 - Effect of soy protein isolate supplementation on biochemical recurrence of prostate cancer after radical prostatectomy
T2 - A randomized trial
AU - Bosland, Maarten C.
AU - Kato, Ikuko
AU - Zeleniuch-Jacquotte, Anne
AU - Schmoll, Joanne
AU - Enk Rueter, Erika
AU - Melamed, Jonathan
AU - Kong, Max Xiangtian
AU - Macias, Virgilia
AU - Kajdacsy-Balla, Andre
AU - Lumey, L. H.
AU - Xie, Hui
AU - Gao, Weihua
AU - Walden, Paul
AU - Lepor, Herbert
AU - Taneja, Samir S.
AU - Randolph, Carla
AU - Schlicht, Michael J.
AU - Meserve-Watanabe, Hiroko
AU - Deaton, Ryan J.
AU - Davies, Joanne A.
PY - 2013/7/10
Y1 - 2013/7/10
N2 - IMPORTANCE: Soy consumption has been suggested to reduce risk or recurrence of prostate cancer, but this has not been tested in a randomized trial with prostate cancer as the end point. OBJECTIVE: To determine whether daily consumption of a soy protein isolate supplement for 2 years reduces the rate of biochemical recurrence of prostate cancer after radical prostatectomy or delays such recurrence. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind trial conducted from July 1997 to May 2010 at 7 US centers comparing daily consumption of a soy protein supplement vs placebo in 177 men at high risk of recurrence after radical prostatectomy for prostate cancer. Supplement intervention was started within 4 months after surgery and continued for up to 2 years, with prostate-specific antigen (PSA) measurements made at 2-month intervals in the first year and every 3 months thereafter. INTERVENTION: Participants were randomized to receive a daily serving of a beverage powder containing 20 g of protein in the form of either soy protein isolate (n=87) or, as placebo, calcium caseinate (n=90). MAIN OUTCOMES AND MEASURES: Biochemical recurrence rate of prostate cancer (defined as development of a PSA level of ≥0.07 ng/mL) over the first 2 years following randomization and time to recurrence. RESULTS: The trial was stopped early for lack of treatment effects at a planned interim analysis with 81 evaluable participants in the intervention group and 78 in the placebo group. Overall, 28.3%of participants developed biochemical recurrence within 2 years of entering the trial (close to the a priori predicted recurrence rate of 30%). Among these, 22 (27.2%) occurred in the intervention group and 23 (29.5%) in the placebo group. The resulting hazard ratio for active treatment was 0.96 (95%CI, 0.53-1.72; log-rank P = .89). Adherence was greater than 90% and there were no apparent adverse events related to supplementation. CONCLUSION AND RELEVANCE: Daily consumption of a beverage powder supplement containing soy protein isolate for 2 years following radical prostatectomy did not reduce biochemical recurrence of prostate cancer in men at high risk of PSA failure. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00765479.
AB - IMPORTANCE: Soy consumption has been suggested to reduce risk or recurrence of prostate cancer, but this has not been tested in a randomized trial with prostate cancer as the end point. OBJECTIVE: To determine whether daily consumption of a soy protein isolate supplement for 2 years reduces the rate of biochemical recurrence of prostate cancer after radical prostatectomy or delays such recurrence. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind trial conducted from July 1997 to May 2010 at 7 US centers comparing daily consumption of a soy protein supplement vs placebo in 177 men at high risk of recurrence after radical prostatectomy for prostate cancer. Supplement intervention was started within 4 months after surgery and continued for up to 2 years, with prostate-specific antigen (PSA) measurements made at 2-month intervals in the first year and every 3 months thereafter. INTERVENTION: Participants were randomized to receive a daily serving of a beverage powder containing 20 g of protein in the form of either soy protein isolate (n=87) or, as placebo, calcium caseinate (n=90). MAIN OUTCOMES AND MEASURES: Biochemical recurrence rate of prostate cancer (defined as development of a PSA level of ≥0.07 ng/mL) over the first 2 years following randomization and time to recurrence. RESULTS: The trial was stopped early for lack of treatment effects at a planned interim analysis with 81 evaluable participants in the intervention group and 78 in the placebo group. Overall, 28.3%of participants developed biochemical recurrence within 2 years of entering the trial (close to the a priori predicted recurrence rate of 30%). Among these, 22 (27.2%) occurred in the intervention group and 23 (29.5%) in the placebo group. The resulting hazard ratio for active treatment was 0.96 (95%CI, 0.53-1.72; log-rank P = .89). Adherence was greater than 90% and there were no apparent adverse events related to supplementation. CONCLUSION AND RELEVANCE: Daily consumption of a beverage powder supplement containing soy protein isolate for 2 years following radical prostatectomy did not reduce biochemical recurrence of prostate cancer in men at high risk of PSA failure. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00765479.
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U2 - 10.1001/jama.2013.7842
DO - 10.1001/jama.2013.7842
M3 - Article
C2 - 23839751
AN - SCOPUS:84880149475
SN - 0098-7484
VL - 310
SP - 170
EP - 178
JO - JAMA
JF - JAMA
IS - 2
ER -