Long-term outcomes of the first prospective study of active surveillance for prostate cancer in Japan.

Abstract

Background: Active surveillance for prostate cancer was initiated in the early 2000s. We assessed the long-term outcomes of active surveillance in Japan.

Methods: This multicenter prospective observational cohort study enrolled men aged 50-80 years with stage cT1cN0M0 prostate cancer in 2002 and 2003. The eligibility criteria included serum prostate-specific antigen level ≤ 20 ng/mL, ≤ 2 positive cores per 6-12 biopsy samples, Gleason score ≤ 6, and cancer involvement < 50% in the positive core. Patients were encouraged to undergo active surveillance. Prostate-specific antigen levels were measured bimonthly for 6 months and every 3 months thereafter. Triggers for recommending treatment were prostate-specific antigen doubling time of < 2 years and pathological progression on repeat biopsy.

Results: Among 134 patients, 118 underwent active surveillance. The median age, prostate-specific antigen level at diagnosis, and maximum cancer occupancy were 70 years, 6.5 ng/mL, and 11.2%, respectively. Ninety-one patients had only one positive cancer core. The median observation period was 10.7 years. At 1 year, 65.7% underwent a repeat biopsy, and 37% of patients experienced pathological progression. The active surveillance continuation rates at 5, 10, and 15 years were 28%, 9%, and 4%, respectively. One prostate cancer-related death occurred in a patient who refused treatment despite pathological progression at the one-year repeat biopsy.

Conclusion: Active surveillance according to this study protocol was associated with conversion to the next treatment without delay, when indicated, despite the selection criteria and follow-up protocols being less rigorous than those recommended in current international guidelines.