Secondary chemoprevention of localized prostate cancer by short-term androgen deprivation to select indolent tumors suitable for active surveillance: a prospective pilot phase II study

To investigate the impact of 3-month androgen deprivation therapy (st-ADT) a secondary chemoprevention of indolent-localized prostate cancer (PCa). A prospective phase II study enrolled men over 4 years with low-risk PCa and the following characteristics: PSA < 10 ng/mL, Gleason score of 6 (3 + 3) or less, three positive cores or less, and tumor stage T2a or less. Patients received a single sub-cutaneous injection of 22.5 mg of leuprolide acetate with Atrigel 3-month depot associated with a daily oral intake of bicalutamide 50 mg/day during 15 days around the injection. Follow-up included PSA and bioavailable testosterone blood tests every 3 months and yearly surveillance biopsies. Primary end point was the presence of PCa on biopsy at last follow-up. Secondary end points were detailed pathological features and adverse events. Overall, 98 men were included and 45 of them (45.9 %) had a negative biopsy after a median follow-up of 13 months [11-19.5]. Of the 53 patients with positive biopsy, 17 had pathologic progression because of upgraded Gleason score (11 patients), four or more positive cores (three patients) or both (three patients). The only significant predictive factor biopsy outcome was the number of positive cores at diagnosis. Secondary chemoprevention by st-ADT for localized PCa could be useful to pinpoint indolent tumors suitable for AS. Indeed, after st-ADT nearly one patient out of two had negative biopsies and 17 % had pathological progression. This is an innovative option to consider as an alternative to current AS protocols contingent upon confirmation in subsequent studies.