To investigate the expression of P53 in rectal cancer tissues and its relationship with the sensitivity of preoperative concurrent chemoradiotherapy.

Eighty-two cases of rectal adenocarcinoma were selected from May 2012 to November 2013 in the Second Affiliated Hospital of Hainan Medical College. Patients underwent rectal resection 4-6 weeks after the end of preoperative chemoradiotherapy. The sensitivity of concurrent chemoradiotherapy was evaluated according to RCRG. The proportion of P53 protein positive cells before and after chemoradiotherapy was detected. The influencing factors of pathological remission of preoperative concurrent chemoradiotherapy were analyzed by Logistic regression. The patients were followed up to evaluate the survival of different pathological RCRG classification.

Thirty-eight cases (46.34%) had complete remission (G1) and sixty-five cases (79.29%) were sensitive to chemoradiotherapy (G1+G2). The content of P53 protein decreased significantly after radiotherapy and chemotherapy (Z=-3.611, P<0.05). High expression of P53 (OR=1.853, 95% CI: 1.144-3.002, P=0.012), clinical decline (OR=1.982, 95% CI: 1.268-3.098, P=0.003) were independent risk factors for preoperative chemoradiotherapy sensitivity of rectal cancer. The median survival time of all patients was (46.3±1.4) months, of which the median survival time of (G1+G2) patients was (71.3±2.4) months, and the median survival time of G3 patients was (38.2±2.1) months. The difference between survival time and pathological effective course after radiotherapy and chemotherapy was statistically significant (P=0.036).

P53 protein expression in rectal cancer tumor tissues is significantly decreased after chemoradiotherapy. Patients with high expression of P53 are more sensitive to the treatment, which displays good prognosis value to assess the clinical response of neoadjuvant radiotherapy and chemotherapy in patients with locally advanced rectal cancer.