To explore the prognostic value of positive lymph node metastasis number in patients with advanced gallbladder cancer after radical resection and to establish a survival nomogram model for prediction.

Clinical data of 158 patients with advanced gallbladder cancer who underwent radical resection in the First Affiliated Hospital of Xi'an Jiaotong University from January 2008 to December 2013 were analyzed retrospectively. The informed consents of all patients were obtained and the local ethical committee approval was received. There were 44 males and 114 females, with an average age of (61±11) years. Survival analysis was performed using Kaplan-Meier survival curve and Log-rank test. The factors influencing the patients' prognosis were screened by Cox multivariate analysis. A nomogram model for the postoperative prognosis was established and was evaluated by consistency index (C-index).

Lymph node metastasis was observed in 46.8%(74/158) of the patients. The median number of dissected lymph nodes was 6.5(1.0-22.0). There were 1.5(0-12.0) positive lymph nodes with a positive rate 25%(0-100%). The median survival time was 29.0 months. The 1-, 3-, 5-year accumulate survival rate was 62.0%, 47.4% and 42.8%, respectively. Multivariate analysis showed that the independent factors influencing the patients' prognosis were T staging, incisal margin, pathological grading and number of positive lymph nodes (RR=2.446, 2.694, 1.897, 2.892; P<0.05). A nomogram model for survival prediction was established based on the 4 independent factors, and the 3- and 5-year C-index was 0.797 and 0.794, respectively.

It can be used to evaluate the lymphatic status of patients with advanced gallbladder cancer and to assist the analysis of patient's survival through observing the positive lymph node metastasis. The survival nomogram model based on T staging, incisal margin, pathological grading and number of positive lymph node metastasis can help to make an individualized survival prediction for the patients.