Clinical Findings and Treatment Outcomes in Patients with Extraprostatic Extension Identified on Prostate Biopsy

Purpose: We describe histopathological, clinical and imaging findings among men with extraprostatic extension on prostate biopsy.

Materials and methods: We searched our institutional pathology database between 2004 and 2015 for pathology reports detailing extraprostatic extension on prostate biopsy in untreated patients. Patient characteristics, biopsy features, imaging interpretations and outcomes were examined.

Results: Of 19,950 patients with prostate cancer on biopsy 112 had extraprostatic extension for a prevalence of 0.6% (95% CI 0.5-0.7). Most of the 112 patients had palpable, high grade (Gleason score 9), high volume disease, which was classified as high risk in 34 (30%), locally advanced in 17 (15%) and metastatic in 39 (35%). Most patients had 1 or 2 cores with extraprostatic extension, typically at the base and with concomitant perineural invasion. Extraprostatic extension was identified by magnetic resonance imaging in 32 of 40 patients (80%). Median followup in those who did not die was 1.3 years (IQR 0.3-4.2). Outcomes in the subgroup of 24 men treated with radical prostatectomy were consistent with high risk disease, including positive margins in 14 (58%), seminal vesicle invasion in 10 (42%) and lymph node invasion in 11 (46%). In the entire cohort the 3-year risks of metastasis and overall mortality were 32% (95% CI 22-44) and 37% (95% CI 27-50), respectively. We did not find evidence to suggest that the proportion of cores with cancer that also had extraprostatic extension was associated with overall mortality (p = 0.09).

Conclusions: Extraprostatic extension is a rare finding on prostate biopsy. It is strongly associated with other features of aggressive prostate cancer.