Presentation Authors: Jinge Zhao*, Junru Chen, Mengni Zhang, Xin Tang, Guangxi Sun, Pengfei Shen, Ni Chen, Hao Zeng, Chengdu, China, People's Republic of
Introduction: The clinical value of perineural invasion (PNI) in localized prostate cancer (PCa) has been widely explored. However, till now, there's no study focusing on the significance of PNI in metastatic PCa (mPCa). Since PNI was closely related to metastases, it is of great necessity and importance to investigate its prognostic value in patients with mPCa.
Methods: Data of 515 mPCa patients between 2012-2018 were retrospectively studied. PNI was identified by prostate biopsy and was classified into unifocal (uni-PNI) and multifocal PNI (multi-PNI). The prognostic value of PNI was tested by Kaplan-Meier curves and Cox regression. The endpoints were castration-resistant PCa free survival (CFS) and overall survival (OS)
Results: PNI was detected in 170/515 (33.0%) cases. Among them 73/170 (42.9%) and 97/170 (57.1%) harboured uni- and multi-PNI, respectively. Patients with PNI were associated with statistically shorter median CFS (mCFS) and numerically shorter median OS (mOS) than those without PNI (mCFS: 15.4- vs. 18.5-Mo, p=0.015; mOS: 63.8- vs. 71.4-Mo, p=0.108). Cases harbouring multi-PNI had poorer prognosis than those with uni-PNI (mCFS: 12.4- vs. 18.0-Mo, p=0.040; mOS: 39.7-Mo vs. NR, p=0.018) or those without PNI (mCFS: 12.4- vs. 18.5-Mo, p=0.002; mOS: 39.7- vs. 71.4-Mo, p=0.002). Totally, neither uni-PNI nor multi-PNI was a risk factor in multivariate analyses. Remarkably, in subanalyses, the prognostic effect of multi-PNI was achieved mostly in cases with favorable baseline factors, while for men harbouring unfavorable baseline factors, multi-PNI was no longer a prognosticator (Figure 1). Multi-PNI was an independent prognosticator in multivariate analyses for cases with favorable/intermediate risk mPCa (CFS: HR: 1.705, 95%CI: 1.029-2.825, p=0.038; OS: HR: 3.294, 95%CI: 1.464-7.413, p=0.004) but not for those with high risk mPCa.
Conclusions: This study filled the blank of the clinical significance of PNI in mPCa. Multi-PNI could distinguish men with relatively poor prognosis from cases initially regarded as with favorable survival outcomes by other prognosticators, and thus, avoid disease underestimation in those patients. Our finding would help clinicians deeper understanding the heterogeneity of mPCa and making better individualized therapeutic strategy.
Source of Funding: This work was supported by the National Natural Science Foundation of China (NSFC 81672547, 81402110, and 81272820); Science and Technology Support Program of Sichuan Province (2015SZ0142); The 1.3.5 project for disciplines of excellence, West China Hospi