Prospective evaluation of selection criteria for active surveillance in Japanese patients with stage T1cN0M0 prostate cancer

Abstract

Objective: Selection criteria for active surveillance (AS) program of localized prostate cancer remain to be standardized. The purpose was to evaluate the validity of selection criteria and investigate the feasibility of this AS program.

Methods: Patients meeting the criteria (i) stage T1cN0M0, (ii) age 50-80, (iii) serum prostate-specific antigen (PSA) </=20 ng/ml, (iv) one or two positive cores per 6-12 systematic biopsy cores, (v) Gleason score </=6, and (vi) cancer involvement in positive core </=50% were enrolled and encouraged to start AS for at least 6 months during the period between January 2002 and December 2003. PSA was measured bimonthly for 6 months and every 3 months thereafter. Trigger of treatment recommendation was PSA-doubling time (PSADT) of </=2 years or pathological progression at re-biopsy. Primary endpoint was '%PSADT > 2y', which was defined as the proportion of patients who showed PSADT assessed at 6 months >2 years out of all the patients who chose AS. Point estimate of '%PSADT > 2y' was expected to be >80%.

Results: One hundred and eighteen patients opted for AS and 16 chose immediate treatment at enrollment. PSADT for the initial 6 months based on four measurements could be assessed in 106 patients. Intent-to-treat analysis of '%PSADT > 2y' was 71.2% (84/118, 95% CI: 62.1-79.2). Pathological progression rate at 1-year re-biopsy was 33%. Fifty-four (46%) patients remained on AS for maximal observation of 54 months. General health-related QOL in patients undergoing AS was not impaired.

Conclusions: The primary endpoint, '%PSADT > 2y', did not meet the pre-specified decision criteria. Further prospective study with revised program and endpoint is needed.