Prognostic factors of long term survival in gastric cancer. Introduction of the new N+/T index

Abstract

Background: The identification of survival prognostic factors for gastric cancer, allows us to create clinical guidelines. Chile has a deficit in the analysis of long-term survival prognostic factors.

Aim: To assess different prognostic factors of long-term survival in gastric cancer. Determine the survival rate at 5 and 10-years post gastrectomy, and the value of a new prognostic factor of long-term survival called N+/T. Material and Method: Prospective study of the oncological database of the Clinical Hospital of the University of Chile between May 2004 and May 2012.

Results: A total of 284 patients were included, 65.4% were men and the mean age was 64.5 years. Seventy-five percent were advanced gastric cancer, 72.5% of the patients required a total gastrectomy. The lymphadenectomy practiced was D2 in 85.2%, and average lymph node harvest was 30 lymph nodes. The postoperative morbidity and mortality was 17.2% and 1.7% respectively. The average global survival was 69.9 months, the 5-year survival was 56.9% and the 10-year survival was 53.4%. The N+/T index presented a statistically significant difference in the global survival of all the subgroups (p < 0.0001). The multivariate analysis showed that the significant variables were: N+/T index (p = 0.0001, OR: 1.1 [1.05-1.12]), LNR (p = 0.0001, OR: 5.8 [1.04-15.6]), age (p = 0.008, OR: 1.03 [1.00-1.06]), lymphovascular permeation (p = 0.0001, OR: 2.19 [1.49-3.23]), T classification (p = 0.03, OR: 3.4 [1.10-8.93]), N classification(p = 0.001, OR: 1.06 [1.02-1.10]), and TNM stage (p = 0.004, OR: 1.03 [1.01-1.06]). The areas under the ROC curves of the N+/T, LNR and T classification, were 0.789, 0.786 and 0.790 respectively (p = 0.96).

Conclusion: The independent prognostic factors of long-term survival were N+/T index, LNR, age, lymphovascular permeation, T classification, N classification and TNM stage. Concomitantly, a new prognostic factor has been created to assess survival in gastric cancer, the N+/T index.