Objectives: To determine whether patient sex has a significant effect on long-term outcomes post curative resection of non-small-cell lung cancer.
Methods: We retrospectively analysed a prospectively validated thoracic surgery database (n = 4212), from a single institution, from September 2001 to October 2012. Univariate, Cox multivariate and propensity analysis was performed. Long-term follow-up was carried out via the National Strategic Tracing Service that operates in the United Kingdom.
Results: One hundred per cent follow-up was achieved. Overall institutional in-hospital mortality was 2.0% for all thoracic resections. Median survival was 2.78 years (range 0-13 years). Two thousand two hundred and thirty-three males and 1979 females were included. Kaplan-Meier survival of all the patients demonstrated superior survival of females for all stages, P = 0.0003, and stage I, P = 0.0006. Female sex conferred no survival advantage in stage II, P = 0.7, and IIIa, P = 0.1. Sub-analysis by histological type demonstrated that females had superior survival with adenocarcinoma compared with males, P < 0.001, but no sex difference existed with squamous carcinomas, P = 0.2. Cox analyses demonstrated that female sex was an advantageous prognostic factor for the entire study group [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.69-0.96] and Stage I only (HR 0.70, 95% CI 0.57-0.63). Sex was of no significance in Stage II and IIIa disease with regard to survival. Sub-analysis demonstrated that female sex was not a significant factor determining survival in patients with squamous carcinoma; however, it was significantly associated with increased survival in patients with adenocarcinoma (HR 0.63, 95% CI 0.51-0.78). A 1:1 propensity analysis confirmed the above findings.
Conclusion: Propensity matching and Cox multivariate regression analysis confirmed the univariate finding that female sex is only associated with improved survival in patients with Stage I adenocarcinoma. Patient sex does not affect survival of patients with squamous carcinoma.
Keywords: Female; Lung cancer; Survival.