Reevaluation of survival and prognostic factors in pathologic stage I lung adenocarcinoma by the new 2009 TNM classification

The incidence of lung adenocarcinoma has been increased significantly year by year. In this histologic type, complete surgical resection is commonly chosen as treatment method at the initial stages. However, the postoperative survival rate remains unsatisfactory even within the stage I. The purpose of this study is to investigate the factors related with prognosis in stage I lung adenocarcinoma after surgical resection. In this manuscript, a retrospective study was performed. Survival rates were calculated by the Kaplan-Meier method, and for multivariate analyses, Cox proportional hazards regression model was used. The results indicated that a total of 531 patients were included. Overall 5-year survival was 81.2 %. Age, sex, pathologic stage, T category, tumor size, differentiation, necrosis, visceral pleural invasion (VPI), lymphatic vessel or vascular invasion, and serum carcinoembryonic antigen (CEA) were significantly associated with 5-year overall survival of the patients with Kaplan-Meier analysis. Moreover, on multivariate analyses, seven variables were shown to be independent prognostic factors, including differentiation (hazard ratios (HR), 1.357), VPI (HR, 0.551), lymphatic vessel or vascular invasion (HR, 0.533), necrosis (HR, 1.671), age (HR, 1.519), pathological stage (HR, 4.477), and CEA (HR, 2.099). In conclusion, the most important prognostic factor is pathologic stage. Other adverse prognostic factors include differentiation, VPI, lymphatic vessel or vascular invasion, necrosis, age, and CEA.