Assessing the effectiveness of mesorectal excision in rectal cancer

Abstract

PURPOSE: The aim of this study was to determine whether the number of involved or uninvolved lymph nodes in resected specimens can be used to predict the effectiveness of surgical resection for rectal cancer. METHODS: Local recurrence and survival rates for 118 patients undergoing curative resection for rectal carcinoma, without adjuvant therapy, were retrospectively studied. RESULTS: Mean follow-up was 62±37 months. Mean number of involved or uninvolved lymph nodes per resected specimen was 12±7. Overall local recurrence rate was 15.2 percent. In patients without involved lymph nodes (N0 patients) and with T1 or T2 tumors, the local recurrence rate ranged from 0 to 8 percent (not significant), depending on the number of lymph nodes on the specimen. In patients without involved lymph nodes and those with T3 tumors, the actuarial survival rate at ten years was significantly lower (P<0.05), and the local recurrence rate was higher (P<0.02) in patients with fewer than ten lymph nodes than in those with more than ten nodes. In patients with involved lymph nodes, the mean number of nodes on the resected specimen correlated closely with the mean number involved by the tumor. CONCLUSION: The assessment of the effectiveness of rectal excision for cancer is in part helped by the number of involved or uninvolved lymph nodes found on the resected specimen. This is of particular interest in patients without involved lymph nodes and those having infiltrating T3 tumors, for whom the long-term survival and local recurrence rates were significantly better when more than ten lymph nodes were present. On the other hand, when fewer than ten nodes were found, whatever the cause, adjuvant radiotherapy had to be considered, because of the high risk of local failure rate.