Perineural Invasion Is a Prognostic Factor and Treatment Indicator in Patients with Rectal Cancer Undergoing Curative Surgery: 2000-2011 Data from a Single-center Study.

Background/Aim: The aim of the present study was to investigate whether perineural invasion (PNI) was a prognostic index for patients who underwent curative surgery for Dukes' grade B and C rectal cancer. Patients and Methods: A total of 645 patients with rectal cancer between January 2000 and December 2011; 363 with Dukes' B or C stages who did not undergo chemoradiotherapy were reviewed. Results: Of 363 patients, 83 (22.9%) were PNI-positive. The 5-year overall survival and disease-specific survival rates were significantly worse for patients with PNI-positive Dukes' B or C disease compared to those with PNI-negative disease. There was no significant difference in the recurrence pattern (hematogenous or lymphatic spread), but patients with PNI-positive disease had a significantly higher rate of recurrence compared to those with PNI-negative disease (p<0.001). Conclusion: PNI was a significant prognostic factor in rectal cancer, and the PNI status in primary rectal cancer pathology specimens should be considered for therapy stratification.