[Clinical study of perineural invasion in patients with rectal cancer].

Objective: To investigate the clinical significance of perineural invasion(PNI) in rectal cancer.

Methods: Clinical data of 204 patients undergoing resection of low rectal cancer from January 2003 to January 2005 at the First People's Hospital of Chenzhou were analyzed retrospectively. Paraffin sections of surgical specimens from all the patients who underwent resection of low rectal cancer were stained with HE. PNI-positive was defined as infiltration of carcinoma cell into the perineurium or neural fascia. The association of PNI with clinicopathologic features and prognosis of rectal cancer was analyzed.

Results: PNI was positive in 31.9%(65/204) of the patients. The tumor size, depth of invasion, lymph node metastasis, TNM stage, tumor growth pattern, histologic grade, tumor resection were significantly associated with PNI. The overall survival time of the PNI-positive patients was shorter than that of the PNI-negative patients[(43.8±1.5) months vs.(57.2±1.5) months, P<0.01]. Furthermore, the overall survival time of the PNI-positive stage II( patients was shorter than that of the stage III( patients [(46.5±3.2) months vs. (55.7±1.2) months, P<0.05].

Conclusion: PNI can be used as one of the indicators to predict the prognosis of patients with rectal cancer.