In the era of total mesorectal excision: adjuvant radiotherapy may be unnecessary for pT3N0 rectal cancer

BACKGROUND: Due to the Total Mesorectal Excision (TME) surgery made a good local control,the role of radiotherapy in the treatment of pT3N0 rectal cancer is debated and whether this group of patiens were overtreated has been a controversy recently. This study aimed to evaluate the value of adjuvant radiation after TME and survival outcome for patients with pT3N0 rectal adenocarcinoma. METHODS: From January 2003 to December 2011, a total of 141 patients with pT3N0 rectal cancer after radical resection with the principle of Total Mesorectal Excision (TME) were enrolled. Among them, 42 patients (29.8%) got adjuvant chemotherapy (CT) and the remaining cohort received chemoradiotherapy (CRT). The 5-year overall survival rate (OS), 5-year disease free survival rate (DFS), 5-year local recurrence free survival rate (LRFS), 5-year local recurrence rate (LRR) and the prognostic factor of this cohort were analyzed. RESULTS: The median follow-up interval time was 44 months. The 5-year OS and DFS rates were 82.4% and 71.9% for the whole group. There were no significant differences in 5-year OS (83.3% vs 72.4%, P = 0.931) or LRFS rates (81.7% vs 74.5%, P = 0.157) for patients between CT group and CRT group. Multivariate cox regression analysis suggests that preoperative serum CEA level, number of lymph nodes inspected, perirectal fat infiltration were independent prognostic factors for 5-year DFS. The recurrence rate was not affected by radiotherapy for patients with lower and midrectal cancer. CONCLUSIONS: For the patients with pT3N0 rectal cancer, addition radiation after TME surgery made no significant differences in survival rate and local recurrence rate. The effect of adjuvant radiotherapy needs further evaluation.