Prognostic Significance Of Lymph Node Status And Lymph Node Ratio In Rectal Cancer After Neoadjuvant Chemoradiotherapy

Objective: The primary aim of this study was to explore the effect of pathological stage yp N and lymph node ratio(LNR) on prognosis for low rectal cancer after neoadjuvant chemoradiotherapy(CRT).Methods: 371 patients with low rectal cancer who had received CRT followed by curative surgery, treated from March 2007 to October 2014, were retrospectively analyzed. The disease-free survival(DFS) and overall survival(OS)were compared based on yp N staging and the LNR.Results:A total of 371 patients were classified as yp N+ in 107(28.8%), yp N1 in 80(21.6%), and yp N2 in 27(7.3%). Among the 371 cases, 107 cases had a LNR?0.035,265 cases had LNR< 0.035, respectively. Univariate analysis showed that yp T stage(P<0.001), yp N status(P<0.001), LNR(P<0.001), RCRG(P=0.005) and the preoperative CA199 level(P=0.048) were significant prognostic factors for DFS. Age(P=0.024), yp T stage(P=0.03), yp N status(P=0.006), LNR(P=0.005) and the preoperative CA199 level(P =0.012) were the prognostic factors for OS(P<0.05).Multivariate analysis indicated that LNR was an independent prognostic factor for DFS and OS(P<0.05 for both). yp T was significant prognostic factor only for DFS(P<0.05). Age was significant prognostic factor only for OS(P<0.05). yp N stage had no significant effect on DFS or OS(P>0.05 for both).Conclusions: LNR was the independent prognostic factor for patients with low rectal cancer who had received Neo-CRT followed by R0 resection. LNR can be used as one of independent prognostic predictors accompanying with yp N categories, especially in patient with harvested lymph node less than 12.