Value of postoperative adjuvant radiotherapy for pT3N0 rectal cancer

Abstract

Objective To evaluate the value of adjuvant radiotherapy after radical resection for pT3N0 rectal cancer. Methods The clinical data of 125 patients with pT3N0 rectal cancer who were diagnosed and given total mesorectal excision in our hospital from 2003 to 2010 were retrospectively analyzed. All patients received postoperative adjuvant chemotherapy, while 40 out of them received postoperative adjuvant radiotherapy in addition. Survival rates were estimated using the Kaplan-Meier method, and univariate prognostic analysis was performed using the log-rank test. Multivariate analysis of influencing factors for local recurrence(LR)rate was performed using the Cox regression model. Results The 5-year sample size was 35. The 5-year overall survival(OS)and disease-free survival(DFS)rates were 82. 3% and 72. 4%, respectively. There was no significant difference in the 5-year OS rate between the postoperative chemoradiotherapy group and the postoperative chemotherapy group(12% vs. 83%, P= 0.911). Multivariate analysis suggested that the number of lymph nodes and perirectal fat infiltration were independent prognostic factors for LR rate(P = 0. 045 ;P = 0. 021). There was no significant difference in LR rate between the low-risk group(no high-risk factors)and the high-risk group(the number of high-risk factors ≥1)(2. 5% vs.11.8%, P=0. 060). Conclusions Postoperative radiotherapy cannot improve the OS and LR rates for pT3N0 rectal cancer without any high-risk factors. The value of postoperative adjuvant radiotherapy for pT3N0 rectal cancer needs further evaluation. Key words: Rectal neoplasms/post-operative radiotherapy; Rectal neoplasms/post-operative chemotherapy; Prognosis factors