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

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.