Effect of Sulforaphane in Men with Biochemical Recurrence after Radical Prostatectomy

Abstract

Increases in serum levels of prostate-specific antigen (PSA) occur commonly in prostate cancer after radical prostatectomy and are designated "biochemical recurrence." Since the phytochemical sulforaphane (SF) has been studied extensively as an anticancer agent, we performed a double-blinded, randomized, placebo-controlled multicenter trial with SF in 78 patients (mean age 69±6 years) with rising PSA levels after radical prostatectomy. Treatment comprised daily oral administration of 60 mg of a stabilized free SF for 6 months (M0 to M6) followed by 2 months without treatment (M6 to M8). The study was designed to detect a 0.012 log (ng/ml)/month decrease in the log PSA slope in the SF group from M0 to M6. The primary end-point was not reached. For secondary end-points, median log PSA slopes were consistently lower in SF-treated men. Mean changes in PSA levels between M6 and M0 were significantly lower in the SF group (+0.099 ± 0.341 ng/ml) compared with placebo (+0.620 ± 1.417 ng/ml; p = 0.0433). PSA doubling time was 86% longer in the SF than in the placebo group (28.9 and 15.5 months, respectively). PSA increases >20% at M6 were significantly greater in the placebo group (71.8%) than in the SF group (44.4%); p=0.0163. Compliance and tolerance were very good. SF effects were prominent within 3 months of intervention (M3 to M6). After treatment, PSA slopes from M6 to M8 remained the same in the two arms. Daily administration of free SF shows promise in managing biochemical recurrences in prostate cancer after radical prostatectomy.