Prognostic Value Of The Number Of Lymph Nodes After Neoadjuvant Chemoradiotherapy For Rectal Cancer

Objective To investigate the prognosis between the number of lymph nodes retrieved of rectal cancer after neoadjuvant chemoradiotherapy.Methods Retrospective analysis of 373 patients in the neoadjuvant chemotherapy of locally advanced low rectal cancer patients with clinical and pathological data, survival and recurrence data. The patients were divided into two group according to the number lymph nodes, using the Kaplan Meier method to analysis the prognosis survival between the two groups.Results Patients had a median of 12 lymph nodes examined after preoperative chemoradiation,and the number of lymph nodes was significantly correlated with RCRG stage, preoperative tumor distance from the anal verge, tumor size, pathological N staging.Multivariate linear regression analysis showed that RCRG stage(r = 0.143,P=0.008), preoperative tumor distance from the anal verge(r = 0.172,P = 0.001), yp N stage(r = 0.136,P = 0.010) are independent risk factors for the number of lymph retrieved after neoadjuvant chemoradiotherapy for rectal cancer..Compared with patients who had <12 lymph nodes examined, patients who had ≥12 lymph nodes had no significant difference 3-year disease-free survival(73.1% vs 71.6%,P = 0.8351). Stratified analysis show that compared with patients who had <10 lymph nodes examined, patients who had ≥10 lymph nodes had significant difference 3-year DFS of low rectal cancer with insensitive to radiotherapy and chemotherapy(P = 0.038). COX regression revealed that yp N stage(HR = 1.173,P<0.001), RCRG stage(HR = 1.449,P = 0.017) are the independent prognostic factor for DFS.Conclusion The cut-off of 12 lymph nodes does not influence survival and should not be considered for cancer-specific prediction of patients having neoadjuvant chemoradiotherapy. Patients who had <10 lymph nodes indicates poor prognosis of low rectal cancer with insensitive to radiotherapy and chemotherapy.