Adjuvant chemotherapy for the perineural invasion of colorectal cancer.

BACKGROUND: To evaluate the association of perineural invasion (PNI) with outcomes in patients after colorectal resection of colorectal cancer (CRC) and to assess the effect of PNI on the response to adjuvant chemotherapy.

PATIENTS AND METHODS: Data were retrospectively reviewed for 178 patients with consecutive stages I-III CRC who underwent curative surgery between January 1999 and December 2004. PNI data were examined, and the overall survival (OS) and disease-free survival rates were analyzed.

RESULTS: PNI was detected in 36 of 178 patients (20%) and positively correlated with lymphatic invasion (P = 0.020), venous invasion (P = 0.037), and the incidence of metastasis or recurrence (P = 0.029). Five-year disease-free survival was 46% and 68% (P < 0.001) and the 5-y OS was 64% and 80% (P < 0.001) for patients with and without PNI, respectively. In stage III CRC, multiple regression analysis identified PNI as a strong negative prognostic factor of OS; among PNI-positive patients, median OS with adjuvant chemotherapy was almost twofold higher than that without adjuvant chemotherapy (6 versus 2.8 y; P = 0.017).

CONCLUSIONS: PNI was a poor predictor of survival among patients with stage III CRC, and adjuvant chemotherapy may attenuate the adverse effects of PNI on survival.