Analysis of efficacy and prognostic factors of postoperative intensity-modulated radiotherapy with or without chemotherapy in rectal cancer

Abstract

Objective To explore the efficacy and prognostic factors of postoperative intensity-modulated radiotherapy (IMRT) with or without chemotherapy in rectal cancer. Methods A retrospective analysis was performed on the clinical data of 218 patients with rectal cancer, who underwent postoperative IMRT in our hospital from January 2009 to December 2013.The Kaplan-Meier method was used to calculate survival rate; the log-rank test was used for survival difference analysis and univariate prognostic analysis; the Cox regression model was used for multivariate prognostic analysis. Results The follow-up rate was 97.7%. The 1-and 3-year overall survival rates were 90.8% and 75.2%, respectively, the 1-and 3-year disease-free survival rates were 85.3% and 70.5%, respectively, and the 1-and 3-year locoregional recurrence-free survival rates were 96.7% and 88.1%, respectively. The incidence of grade 3-4 acute adverse reactions was 28.4%, mainly manifested as leukopenia (13.8%) and diarrhea (11.0%). Univariate prognostic analysis showed that preoperative carcinoembryonic antigen (CEA) and CA199 levels, maximum tumor diameter, tumor location, degree of differentiation, depth of tumor invasion, number of lymph node metastases, TNM stage, perineural invasion, surgical procedure, total mesorectal excision, preoperative bowel obstruction, and preoperative anemia were the predictors of survival (P=0.006, 0.000, 0.000, 0.017, 0.000, 0.016, 0.000, 0.011, 0.001, 0.006, 0.037 and 0.010). Multivariate prognostic analysis showed that preoperative CEA level, tumor location, TNM stage, preoperative bowel obstruction, and preoperative anemia were the predictors of survival (P=0.000, 0.000, 0.000, 0.001 and 0.001). Conclusions Postoperative IMRT with or without chemotherapy is an effective method for rectal cancer with mild adverse reactions and high compliance. Preoperative CEA level, tumor position, TNM stage, preoperative bowel obstruction, and preoperative anemia are independent prognostic factors for the overall survival. Key words: Rectal neoplasms/radiochemotherapy; Radiotherapy, intensity-modulated radiotherapy; Prognosis