Multivariate analysis of prognostic factors in primary squamous cell vulvar cancer: The role of perineural invasion in recurrence and survival.

OBJECTIVE

to assess the prognostic role in recurrence and survival of perineural invasion (PNI) in vulvar squamous cell cancer (VSCC).

METHODS

Patients underwent primary surgery for VSCC from January 2009 to December 2016 served as the study cohort. We collected demographic, clinical, pathological characteristics and follow-up data, and we compared them among PNI-negative versus -positivepatients. We calculated disease-free survival (DFS) and overall survival (OS) using Kaplan-Meier and univariate log-rank test. We conducted a multivariate analysis with cox-proportional hazard models for DFS and OS, including age, tumor size, depth of invasion, free tumor margin <8 mm, high-grade histology, lymph vascular space invasion, PNI, extracapsular lymph nodal disease, lymph nodal ratio >0.2 and FIGO Stage 2009 (Early I-II versus Advanced III-IV).

RESULTS

We found 74 patients with a PNI prevalence of 31.1%. The 5-year DFS was favourable for PNI-negative patients (72% versus 18%; p = 0.00). The 5-year OS was 75% versus 35% in favor of PNI-negative patients (p = 0.00). The subgroup analysis conducted among stage confirmed a decreased DFS and OS in PNI-positive patients. Multivariate analysis showed that PNI (HR 2.74; CI95% 1.10-7.13; p = 0.03) and extracapsular lymph nodal disease (HR 13.54; CI95% 2.87-64.07; p = 0.01) are independent prognostic factors for earlier recurrence. OS was significantly reduced in case of PNI (HR 4.93; CI95% 1.33-18.35; p = 0.01) and extracapsular lymph nodal disease (HR 10.63; CI95% 1.65-68.57; p = 0.01).

CONCLUSIONS

PNI is an independent prognostic factor for aggressive behavior and unfavorable course in VSCC and should be considered in adjuvant treatment planning.