Perineural invasion by prostate cancer on MR/US fusion targeted biopsy is associated with extraprostatic extension and early biochemical recurrence after radical prostatectomy.

In recent years, multiparametric magnetic resonance imaging and magnetic resonance/ultrasound fusion targeted biopsy (TB) have become more widely adopted to aid in prostate cancer (PCa) detection. Previously, TB has been found to increase the yield of clinically significant PCa and is more likely to sample the index tumor compared with traditional 12-core extended sextant biopsies. Currently, the prognostic significance of perineural invasion (PNI) when identified on TB (PNI-TB) is unknown. We identified 95 men at 2 tertiary referral centers who underwent TB followed by radical prostatectomy between January 2014 and January 2017. Clinical, radiological, and pathological variables were retrospectively reviewed. PNI was identified on TB in 27 of 95 (28.4%) patients. On multivariable logistic regression, independent predictors of extraprostatic extension were prostate-specific antigen, TB maximum % core involvement, and PNI-TB (all P<.05). Furthermore, Kaplan-Meier analysis demonstrated that PNI-TB was associated with early biochemical recurrence events within 12 months after prostatectomy (log-rank P=.049). Given the increasing adoption of TB for PCa detection in clinical practice, PNI-TB may be useful for PCa risk stratification.