The Impact Of Neoadjuvant Therapy For Locally Advanced Rectal Cancer On Lymph Nodes Retrieval

Objective To study the impact of neoadjuvant therapy for locally advanced middle-low rectal carcinoma on lymph nodes retrieval Method From January 2005 to June 2008,120 patients with locally advanced middle-low rectal cancer(T2～4 and/or N1-2MO) in Peking Union Medical College Hospital were enrolled into the present study.The patients were divided into two groups.The 54 patients in study group were treated with neoadjuvant therapy (preoperative long course radiation with or without synchronous 5-FU -based chemotherapy) followed by radical resection after 4～6 weeks.The 66 patients in control group was received primary surgery without receiving any neoadjuvant therapy.Surgery and pathological assessment were standardized in all the patients.The general materials,the pathology report of the resected specimen from all the patients and clinical stage of before and after neoadjuvant therapy in control patients were collected.The clinical stage was evaluated before and after neoadjuvant therapy.The yields of total lymph nodes,as well as the tumor-positive lymph nodes of each resected specimen were analyzed statistically and tested.Results Clinical downstage was found in approximately 56%patients with locally advanced rectal carcinoma after neoadjuvant therapy.The number of total lymph nodes and the number of positive lymph nodes from each resected specimen in the study group were significantly lower than that from patients in control group (9.4±6.0 v 13.9±7.1,p=0.O00:0.7±2.4 v 2.2±3.7,p=0.001,respectively). The mean number of lymph nodes retrieved from patients with preoperative adiuvant therapy was lower than 12 with significant difference(t=-3.234, df=53,p=0.002).Conclusions Preoperative radiation of total doses of 50Gy/combined 5-FU-based chemotherapy not only could down- stage T,but also reduced the retrieval rate of total lymph nodes and positive lymph nodes of rectal cancer.It was necessary to retrieve as many evaluated lymph nodes as possible,as the number of lymph nodes retrieved from rectal carcinoma had some prognostic significance.