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." Because the phytochemical sulforaphane has been studied extensively as an anticancer agent, we performed a double-blinded, randomized, placebo-controlled multicenter trial with sulforaphane in 78 patients (mean age, 69 ± 6 years) with increasing PSA levels after radical prostatectomy. Treatment comprised daily oral administration of 60 mg of a stabilized free sulforaphane for 6 months (M0-M6) followed by 2 months without treatment (M6-M8). The study was designed to detect a 0.012 log (ng/mL)/month decrease in the log PSA slope in the sulforaphane group from M0 to M6. The primary endpoint was not reached. For secondary endpoints, median log PSA slopes were consistently lower in sulforaphane-treated men. Mean changes in PSA levels between M6 and M0 were significantly lower in the sulforaphane group (+0.099 ± 0.341 ng/mL) than in placebo (+0.620 ± 1.417 ng/mL; P = 0.0433). PSA doubling time was 86% longer in the sulforaphane 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 sulforaphane group (44.4%);P = 0.0163. Compliance and tolerance were very good. Sulforaphane effects were prominent after 3 months of intervention (M3-M6). After treatment, PSA slopes from M6 to M8 remained the same in the 2 arms. Daily administration of free sulforaphane shows promise in managing biochemical recurrences in prostate cancer after radical prostatectomy.