Gender-specific survival after surgical resection for early stage non-small cell lung cancer

Background: Lung cancer is the leading cause of cancer death worldwide. The incidence and mortality rate of lung cancer in women has increased. Studies have indicated that females with non-small cell lung cancer (NSCLC) have better survival than males. We aimed to examine the impact of gender on 1-, 5-and 10-year survival after surgery for stage I and II NSCLC. Materials and methods: During the period 2003-2013, 692 patients operated for stage I and II NSCLC were prospectively registered. Patients were stratified into four groups according to gender and age over or less than 66 years. The relationship between gender and age on overall survival was investigated. Adjustment for multiple confounders was performed using the Cox proportional hazard regression model. Results: Surgical resection was performed in 368 (53.2%) males and 324 (46.8%) females. During the study period, mortality was 35.2% in younger females, 34.9% in younger males, 42.8% in older females and 51.2% in older males. Stratified by age, there were no significant gender differences with regard to survival [hazard ratio (HR) 1.16, 95% confidence interval (CI) 0.91-1.46, p =.23]. Comparing the younger and the older patients adjusted for confounders, the mortality risk was significantly increased in elderly patients [females, adjusted HR 1.60, 95% CI 1.12-2.28]. Compared with population data, standardized mortality ratio was increased to 4.1 (95% CI 3.5-4.7) in males and to 6.5 (95% CI 5.4-7.6) in females. Conclusion: Overall survival did not differ significantly between males and females. Adjusted for confounding factors, we found a significantly increased mortality risk in elder patients compared to their younger counterparts. However, five-year overall survival of more than 50% for older patients with NSCLC should encourage surgical treatment also in elderly lung cancer patients.