Analysis Of Efficacy And Prognostic Factors Of Postoperative IMRT ± Chemotherapy In Rectal Cancer

Objective: Surgery is the main treatment of rectal cancer, with higher recurrence rate after surgery alone, so the preoperative/postoperative chemoradiotherapy has been standard treatment for locally advanced rectal cancer. Intensity- modulated radiotherapy(IMRT) has been applied widely in clinical practice, but how about its efficacy and whether its toxicity is lower? This study aimed to explore the efficacy and prognostic factors of postoperative 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. Data regarding patient and tumor characteristics, treatment, acute toxicity according to the NCI-CTCAE v3.0, survival and tumor status were collected. A total of 208 patients(95.4%) received chemotherapy, fluorouracil were the main treatment drugs. 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 were used for multivariate prognostic analysis.Results: By November 30, 2014, 5 patients were lost to follow-up, the follow-up rate 97.7%. The 1-and 3- overall survival rates were 90.8% and 75.2%, respectively; the 1-and 3- disease-free survival rates were 85.3% and 70.5%, respectively; and the 1-and 3-locoregional recurrence-free survival rates were 96.7% and 88.1%, respectively. There were no significant differences between concurrent chemoradiotherapy(CCRT) group and sequential chemoradiotherapy(SCRT) group in 3-year overall survival rates(80.1% : 72.4%, P=0.100), 3-year disease-free survival rates(75.3% : 67.3%, P=0.066) and 3-year locoregional recurrence-free survival rates(93.3% : 84.9%, P=0.107). The incidence of grade 3~4 acute adverse reactions was 28.4%, mainly manifested as leukopenia(13.8%) and diarrhea(11.0%). Compared with the SCRT group, the incidence of leukopenia(76.4% : 63.2%, P=0.132), anemia(51.4% : 29.4%, P=0.003), diarrhea(51.4% : 44.1%, P=0.178), radiation-induced dermatitis(29.3% : 25%, P=0.351) and hepatic injury(30.7% : 10.3%, P=0.001) was higher in the CCRT group. Univariate prognostic analysis showed that preoperative carcinoembryonic antigen(CEA) and CA199 levels, maximum tumor diameter, tumor location, degree of differenation, 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, 0.001, 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 location, TNM stage, preoperative bowel obstruction and preoperative anemia are independent prognostic factors for the overall survival.