A negative confirmatory biopsy among men on active surveillance for prostate cancer does not protect them from histologic grade progression

Background: Many men (21-52%) are reported to have no cancer on the second, also known as the confirmatory, biopsy (B2) for prostate cancer active surveillance (AS). If these men had a reduced risk of pathologic progression, particularly grade related, the intensity of their follow-up could be decreased.

Objective: To investigate if men with no cancer on B2 are less likely to undergo subsequent pathologic progression.

Design, setting, and participants: Men were identified from our tertiary care center AS prostate cancer database (1995-2012). Eligibility criteria were prostate-specific antigen (PSA) ≤ 10, cT2 or lower, no Gleason grade 4 or 5, three or fewer positive cores, and no core >50% involved. Only patients with three or more biopsies were selected and then dichotomized on cancer status (yes or no) at B2.

Intervention as outcome measurements and statistical analysis: Pathologic progression was defined as grade (advancement in Gleason score) and/or volume (more than three positive cores, >50% core involved). Progression-free survival was compared. Predictors of progression were investigated using a Cox proportional hazards model.

Results and limitations: Of the 286 patients remaining on AS after B2, 149 (52%) had no cancer and 137 (48%) had cancer. The median follow-up after B2 was 41 mo (interquartile range [IQR]: 26.5-61.9). Progression-free survival at 5 yr was 85.2% versus 67.3% for negative B2 versus cancer on B2, respectively (p = 0.002). Men with no cancer at B2 had a 53% reduction in risk of subsequent progression (hazard ratio [HR]: 0.47; 95% confidence interval [CI], 0.29-0.77; p = 0.003). Subanalysis showed prognostic indicators of volume-related progression were absence of cancer (HR: 0.36; 95% CI, 0.20-0.62; p = 0.0006) and PSA density (HR: 1.79; 95% CI, 1.12-2.89; p = 0.01). The only predictor of grade-related progression was age (HR: 1.05; 95% CI, 1.00-1.10; p = 0.04). Retrospective analysis was the major limitation of the study.

Conclusions: Absence of cancer on B2 is associated with a significantly decreased risk of volume-related but not grade-related progression. This must be considered when counseling men on AS.