Prognostic role of perineural invasion in vulvar squamous cell carcinoma: A systematic review and meta-analysis

The prognostic role of perineural invasion (PNI) in vulvar squamous cell carcinoma (VSCC) has not been fully established since few studies on this topic are currently available in the literature. In the present study, we conducted a systematic review and metanalysis of literature data in order to determine if PNI could be an independent prognostic predictor of patient's survival in VSCC. Four electronic databases (PubMed, ISI Web of Science, Scopus and Google Scholar) were searched from their inception to December 2021 for all studies assessing the prognostic value of PNI in VSCC. Multivariate hazard ratios (HRs) for overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS) were pooled. Six studies with 1048 patients were included. PNI was significantly associated with decreased OS (HR = 2.687; p < 0.001), DSS (HR = 2.375; p = 0.014) and PFS (HR = 1.757; p = 0.001), with no statistical heterogeneity among studies and no significant risk of bias across studies. The present meta-analysis highlights that PNI is independently associated with unfavorable prognosis in patients with VSCC. Therefore, PNI should be included in the pathological report of VSCC and considered in combination with other risk factors as a possible criteria for prognostic assessment adjuvant treatment planning inclusion.