Factors Influence Lymph Node Retrieval after Resection for Rectal Cancer

Introduction: Total lymph node (TLN) count is an important qualifier of cancer evaluation and extensive nodal resection has been associated with lower rates of cancer recurrence; allows for more accurate cancer staging and improved survival following resection for rectal cancer. Aim: To examine the adequacy of lymph node sampling in rectal cancer and the influence of the clinicopathological factors and treatment modalities on the total lymph node yield. Methods: This is a retrospective study includes 409 cases of rectal cancer treated by surgical intervention only (126 cases), or surgery after short or long course chemotherapy (75 and 208 cases respectively). Results: TLN count range from (2-50, mean 12.38). Twelve lymph nodes were found in 49.4% of the specimens with or without neoadjuvent chemo radiatherapy (CRT). Patient treated with surgery only have a significant high total LN yield (mean is 15.53) in comparison with (12.99 and 10.25 for short course CRT and long course CRT respectively, P value <0.001). The number of lymph nodes was significantly correlated with the modality of treatment, anterior quadrant involvement, vascular and perineural invasion, pathological staging, Duke's and Mandard staging. On multivariate only perineural invasion, high tie lymph node involvement, Dukes stage, and tumour load were found to be the main predictors of the number of lymph node yield. Conclusion: The neoadjuvent CRT has a significant effect on the adequacy of lymph node sampling and a negative impact on the lymph nodes retrieved. This negative effect was more prominent with the long term rather than the short term CRT. This should be taken in consideration at the N staging of the tumour to avoid down-staging.