Watchful waiting for localized prostate cancer in the PSA era: what have been the triggers for intervention?

• To report outcomes for patients with localized prostate cancer managed using a watchful waiting strategy at an American centre and to explore factors that have triggered intervention.

• From 1991 to 2005, 218 patients diagnosed with untreated localized prostate cancer were followed at Massachusetts General Hospital with prostate-specific antigen (PSA) monitoring and digital rectal examination (DRE). Re-biopsies were performed in 95 of the patients. • The median follow-up was 6.3 years. Clinical outcomes and features predicting intervention were examined.

• At diagnosis, the median PSA level was 5.4 ng/mL. The Gleason score (GS) distribution was as follows: 95% with GS 6, 4% with GS 7, 1% with GS 8. The clinical T-stage distribution was as follows: 6% with T1a-b, 84% with T1c, 10% with T2. The median age was 71 years. • At 10 years, the overall survival was 79%, the cause-specific survival was 100%, the rate of distant metastasis was 5%, the rate of salvage androgen deprivation therapy was 15% and the rate of freedom from intervention (FFI) was 70%. • There was a PSA velocity of ≥ 2 ng/mL per year in 16% of patients, and a PSA doubling time of ≤ 3 years in 15% of patients. • Among the 95 re-biopsied men, the GS increased (grade progression) in 25% and the percentage of positive cores increased (volume progression) in 33%. • On multivariate analysis, only PSA doubling time and volume progression were independent predictors of FFI.

• In the present series, watchful waiting was associated with low rates of intervention and cancer progression. • As PSA doubling time and volume progression were the main triggers for intervention, these will be incorporated into the centre's current active surveillance protocol.