Clinical significance of perineural invasion by prostate cancer on magnetic resonance imaging-targeted biopsy

Abstract

Perineural invasion (PNI) by prostate cancer detected on systematic sextant biopsy (S-Bx) has been considered as a key prognosticator. However, the clinical significance of PNI on magnetic resonance imaging-targeted biopsy (T-Bx) needs to be further investigated. We assessed 169 patients undergoing T-Bx with concurrent S-Bx, followed by radical prostatectomy (RP) from 2015 to 2019. In all cases where cancer was detected on T-Bx only (n = 34) or both S-Bx and T-Bx (B-Bx; n = 135), PNI was found in 33 (19.5%) T-Bxs. Compared with no PNI, PNI on T-Bx was associated with higher Grade Group on biopsy/RP, higher pT stage, and lymph node metastasis. Outcome analysis revealed a significant difference in the risk of biochemical recurrence after RP between cases with and without PNI on T-Bx (P = 0.021). Next, in the 135 B-Bx cases, PNI was found on S-Bx only (n = 31), T-Bx only (n = 15), or B-Bx (n = 16). Compared with PNI on S-Bx, B-Bx PNI was associated with higher preoperative prostate-specific antigen, higher biopsy GG, higher pT stage, and larger tumor volume. There were no significant differences in any of the clinicopathologic features examined between cases with PNI on T-Bx only vs. B-Bx. Moreover, in this subgroup of patients, PNI on B-Bx was associated with significantly higher risks of biochemical recurrence, compared with PNI on S-Bx only (P = 0.024) or T-Bx only (P = 0.033). In multivariate analysis, PNI on B-Bx showed significance for recurrence (hazard ratio = 2.787, P = 0.034). The presence of PNI on T-Bx, particularly B-Bx, associated with worse histopathologic features on RP and poorer outcomes might thus be useful for risk stratification.

Keywords: Perineural invasion; Prognosis; Prostate cancer; Radical prostatectomy; Sextant biopsy; Targeted biopsy.