[552] The Clinical Significance of Lymph Node Retrieval Using Fat Clearing Techniques in Rectal Cancer Patients Following Neoadjuvant Chemoradiotherapy

M Berho, H Wang, B Safar, S Wexner. Cleveland Clinic Florida, Weston, FL

Background: Lymph node status is the single most important prognostic predictor in colorectal carcinoma. It has been shown that lymph node retrieveal is decreased in the setting of preoperative chemoradiation (CRT) Fat clearance techniques have been shown to increase lymph node harvest; however its role in clinical practice remains controversial. The aim of this study was to investigate the application of fat clearance in cases following neoadjuvant chemoradiation.
Design: All patients who underwent proctectomy following neoadjuvant CRT were included. The lymph node numbers were recorded and compared between the traditional method and fat clearance method. Other tumor chracteristics including stage and tumor regression factor were also studied. Results were expressed as mean SEM. A p<0.05 was considered significant.
Results: From Jan 1998 to Sep 2007, 237 patients were identified, 157 cases in the neoadjuvant therapy group and 80 cases in the non neoadjuvant therapy group. In both groups, patients were divided into traditional lymph node dissection method group (visualization and palpation) and fat clearance method group. In the non neoadjuvant therapy group, there was no significant difference in the number of positive lymph nodes (P=0.347) or N+ stage (P=0.332) between the two methods, even though the total lymph node harvest was increased significantly by utilizing the fat clearance method (P<0.001). In contrast, the total lymph node retrieval (P<0.001), number of positive lymph nodes (P=0.007) and N+ stage (P=0.006) were all increased by fat clearance in the neoadjuvant group. Moreover, the number of cases with N+ stage was compared between the two methods at different T stage level (T0-T4) to eliminate the background bias and the results were confirmed.
Conclusions: In our experience, the utilization of fat clearance significantly influences lymph node staging in rectal cancer following neoadjuvant chemoradiation. These findings suggest that fat clearance may represent a useful tool in all cases receiving neoadjuvant therapy; a more generalized application in colorectal carcinoma specimens remains controversial and warrants further investigation.
Category: Gastrointestinal

Tuesday, March 10, 2009 8:00 AM

Platform Session: Section C, Tuesday Morning