Metastatic lymph node ratio as an important prognostic factor in advanced gallbladder carcinoma with at least 6 lymph nodes retrieved

Background The metastatic lymph node (LN) ratio (LNR) has shown to be an important prognostic factor in various gastrointestinal malignancies. Nevertheless, the prognostic significance of LNR in gallbladder carcinoma (GBC) remains to be determined.Methods From January 2007 to January 2018, 144 advanced GBC patients (T2-4 stages) who underwent curative surgery with at least 6 LNs retrieved were enrolled. Receiver operating characteristic (ROC) curve was performed to identify the optimal cut-off value for LNR. The clinicopathological features stratified by LNR level were analyzed. Meanwhile, univariate and multivariate Cox regression proportional hazard models were performed to identify risk factors for overall survival (OS).Results The optimal cut-off point for LNR was 0.28 according to the ROC curve. LNR>0.28 was associated with higher rate of D2 LN dissection (P=0.004) and higher tumor stages (P<0.001). Extent of liver resection, extrahepatic bile duct resection, tumor stage, LNR, margin status, tumor differentiation, and perineural invasion were associated with OS in univariate analysis (all P<0.05). GBC patients with LNR <= 0.28 had a significantly longer median OS compared to those with LNR>0.28 (27.5 vs 18 months, P=0.004). Multivariate analysis indicated that tumor stage (T2 vs T3/T4; hazard ratio (HR) 1.596; 95% confidence interval (CI) 1.195-2.132), LNR (<= 0.28 vs >0.28; HR 0.666; 95% CI 0.463-0.958), margin status (R0 vs R1; HR 1.828; 95% CI 1.148-2.910), and tumor differentiation (poorly vs well/moderately; HR 0.670; 95% CI 0.589-0.892) were independent prognostic factors for GBC (all P<0.05).Conclusions LNR is correlated to advanced GBC prognosis and is a potential prognostic factor for advanced GBC with at least 6 LNs retrieved.