Medium-term oncological outcomes for extended vs saturation biopsy and transrectal vs transperineal biopsy in active surveillance for prostate cancer

Objective: To assess, in men undergoing active surveillance (AS) for low-risk prostate cancer, whether saturation or transperineal biopsy altered oncological outcomes, compared with standard transrectal biopsy.

Patients and methods: Retrospective analysis of prospectively collected data from two cohorts with localised prostate cancer (1998-2012) undergoing AS. Prostate cancer-specific, metastasis-free and treatment-free survival, unfavourable disease and significant cancer at radical prostatectomy (RP) were compared for standard (<12 core, median 10) vs saturation (>12 core, median 16), and transrectal vs transperineal biopsy, using multivariate analysis.

Results: In all, 650 men were included in the analysis with a median (mean) follow-up of 55 (67) months. Prostate cancer-specific, metastasis-free and biochemical recurrence-free survival were 100%, 100% and 99% respectively. Radical treatment-free survival at 5 and 10 years were 57% and 45% respectively (median time to treatment 7.5 years). On Kaplan-Meier analysis, saturation biopsy was associated with increased objective biopsy progression requiring treatment (log-rank P = 0.01). On multivariate Cox proportional hazards analysis, saturation biopsy (hazard ratio 1.68, P < 0.01) but not transperineal approach (P = 0.89) was associated with increased objective biopsy progression requiring treatment. On logistic regression analysis of 179 men who underwent RP for objective progression, transperineal biopsy was associated with lower likelihood of unfavourable RP pathology (odds ratio 0.42, P = 0.03) but saturation biopsy did not alter the likelihood (P = 0.25). Neither transperineal nor saturation biopsy altered the likelihood of significant vs insignificant cancer at RP (P = 0.19 and P = 0.41, respectively).

Conclusions: AS achieved satisfactory oncological outcomes. Saturation biopsy increased progression to treatment on AS; longer follow-up is needed to determine if this represents beneficial earlier detection of significant disease or over-treatment. Transperineal biopsy reduced the likelihood of unfavourable disease at RP, possibly due to earlier detection of anterior tumours.