Affact of perineural invasion on the prognosis of patients with rectum cancer FAN Ping, TIAN Jing-zhong, LI Guang-yun, et al. Department of General Surgery, Bozhou People’s Hospital, Bozhou236800, China Corresponding author: FAN Ping, E-mail: dengfang1992@sina.com Abstract Objective To analyze the effect of perineural invasion on evaluating the prognosis of patients with rectal cancer. Methods The clinical data of 213 patients with rectum cancer performed total mesorectal excision (TME) from 2000 to 2007 at Bozhou People’s Hospital were analyzed retrospectively. Paraffin sections of surgical specimens from all the patients who underwent TME were stained with laminin. The effect of PNI on overall survival (OS) in patients with rectum cancer and the association between PNI and other clinical and pathological parameters were analyzed. Results PNI was positive in 62 of all the 213 patients (29.11%). The size of tumors, T stage and clinical stage were related to PNI significantly. The OS of the PNI-positive patients [（23.04±9.95）months] was shorter than that of the PNI-negative patients [（52.10±14.61）months] in the univariate analysis significantly (P<0.01). And at multivariate Cox proportional hazards model of OS analysis, the positivity of PNI appeared to be an independent prognostic factor to OS , which was also influenced by tumor size, lymph node metastasis and clinical stage (P<0.01). Conclusion The incidence of PNI plays an important role in evaluation of the tumor classification, stage and the prognosis of rectum cancer and it could serve as an independent predictor of prognosis of rectum cancer.