Author(s): Kwan W, Duncan G, Van Patten C, Liu M, Lim J, Kwan W, Duncan G, Van Patten C, Liu M, Lim J
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Abstract Our objective was to evaluate the tolerability and effect of a daily soy beverage in prostate cancer patients with biochemical failure after radiotherapy. Patients with rising prostate-specific antigen (PSA) after radical radiation for prostate cancer were instructed to consume 500 ml of soy beverage daily for 6 mo. Tolerability of the soy beverage and compliance were assessed. PSA doubling times before and after the consumption of soy were compared. Thirty-four subjects were enrolled; 5 withdrew before 1 mo of soy for reasons unrelated to soy consumption. All remaining 29 subjects were included in the analysis. Mean consumption of the assigned soy beverage was 93\%. Mild gastrointestinal upset (38\%) not affecting soy consumption was the commonest side effect. PSA showed a declining trend in 4 patients (13.8\%), and there was a > 100\% prolongation of PSA doubling time in 8 patients (27.6\%). However, PSA doubling time also showed a 50\% or more shortening in 5 patients (17.2\%). In our cohort of North American subjects, 6 mo of a daily soy beverage was well tolerated and was associated with a declining trend or more than 2 times prolongation of PSA doubling time in 41\% of subjects. Confirmatory studies are warranted.
This article was published in Nutr Cancer
and referenced in Journal of Cancer Science & Therapy