The prognostic significance of perineural invasion and race in men considering active surveillance

Objective To determine the importance of perineural invasion ( PNI ) on diagnostic biopsy in men enrolled in active surveillance ( AS ). Patients and Methods Eligibility criteria for AS included clinical stage ≤ T 2a and G leason score ≤6, ≤3 cores positive, maximum single core involvement <50%, and total tumour volume ≤5% on diagnostic biopsy. All men received 12‐core confirmation biopsy at ≤6 months. AS ‘failure’ on confirmatory biopsy was defined as failure to meet one or more eligibility criteria. Risk of AS failure was compared in men with and without PNI . Results For the 165 men comprising the study population, the mean ( sd ) age was 66.9 (6.5) years and the median (interquartile, IQR ) PSA level of men at study entry was 4.4 (3.2–6.0) ng/mL. The median ( IQR ) follow‐up was 5.5 (1.1–9.9) months. In all, 8.5% (14/165 men) had PNI on diagnostic biopsy. Compared with those without PNI , men with PNI tended to have more cores involved with cancer, at a mean ( sd ) of 2.0 (0.7) vs 1.6 (0.8) cores ( P = 0.08) but did not have significantly a greater mean ( sd ) total tumour length on diagnostic biopsy, at 3.0 (2.1) vs 2.3 (3.6) mm ( P = 0.27). Men with PNI on diagnostic biopsy were significantly more likely to meet criteria for disease progression on confirmatory biopsy (57% [8/14] vs 21% [32/151]; P = 0.006). PNI remained a significant predictor for AS failure after adjustment for number of positive cores, maximum percentage core involvement, and total tumour length (odds ratio 4.4, 95% confidence interval 1.4–14.2). Conclusions PNI on diagnostic biopsy is associated with disease progression on confirmatory biopsy. The presence of PNI should factor into appropriate patient selection and counselling in AS .