Prognostic effect of perineural invasion in surgically treated esophageal squamous cell carcinoma.

BACKGROUND: Although perineural invasion is a well known prognostic factor used in several cancers, its prognostic role in esophageal squamous cell carcinoma remains controversial. Here, we investigated the prognostic role of perineural invasion in surgically treated esophageal squamous cell carcinoma. METHODS: We retrospectively reviewed the medical records of 316 patients who underwent esophagectomy and lymph node dissection for esophageal squamous cell carcinoma between 2007 and 2016. RESULTS: Overall, 287 men (mean age: 62.73 ± 7.97 years) were included in the study. The median follow-up period was 35.97 ± 30.99 months, perineural invasion was confirmed in 25 patients, and three-year overall and disease-free survival were significantly lower in the perineural invasion group than in the no-perineural invasion group (75.9% vs. 40.0%, p < 0.001; 70.3% vs. 21.6%, p < 0.001). Cumulative incidences of locoregional recurrence and distant metastasis over three years were higher in the perineural invasion group (13.8% vs. 9.6%, p = 0.009 and 52.8% vs. 14.6%, p < 0.001). On performing multivariable analysis, perineural invasion, pathological stage, incomplete resection, and neoadjuvant therapy were adverse risk factors for disease-free survival. The concordance index increased when perineural invasion was included in the model (0.712 vs. 0.723). On subgroup analysis, perineural invasion demonstrated a prognostic value in node-negative patients (79.4% vs. 35.7%, p = 0.012). CONCLUSIONS: Perineural invasion was found to be an adverse risk factor for disease-free survival in surgically treated patients with esophageal squamous cell carcinoma. Close observation and individualized adjuvant therapy may be helpful for patients with perineural invasion.