Background: Small population studies have reported higher survival rates for women than men with non-small cell lung carcinoma (NSCLC). Because human NSCLC cells express estrogen receptors, we evaluated hormonally active and inactive women to identify biologically mediated differences.
Methods: A total of 14,676 US women with stage I through IV primary non-small cell lung cancer (NSCLC) from the 1992 to 1997 Surveillance, Epidemiology, and End Results database were grouped into two categories based on the average menopausal age of 51 years as defined by the American College of Obstetricians and Gynecologists: ages 31 to 50 premenopausal (n = 2,230, 15%) and ages 51 to 70 postmenopausal (n = 12,446, 85%). Extreme ages were excluded. Statistics were calculated with chi(2) or Mann-Whitney tests, Kaplan-Meier estimates with log-rank tests, and Cox proportional hazards models.
Results: Premenopausal women more commonly presented with advanced clinical stage, less favorable histology (adenocarcinoma), and poorly differentiated tumors, and more often underwent pneumonectomies. Surgery with curative intent was performed in 31% premenopausal and 33% postmenopausal women (p = 0.03). Overall survival for premenopausal and postmenopausal women was not significantly different (median 10 and 9 months, all stages; 70 and 71 months, stages I and II). Adjusting for significant covariates (stage, histology, size, grade, extent of surgery), postmenopausal women had higher lung-cancer-related deaths (hazard ratio, 1.14; 95% confidence interval, 1.03 to 1.27).
Conclusions: Premenopausal women presented more often with advanced disease and underwent more extensive resection, yet had survival advantage after covariate adjustment. Additionally, postmenopausal women had a survival advantage compared with their male counterparts. Results suggest that estrogen exposure creates a milieu that may confer a protective effect through some yet unknown mechanisms that determine outcome of the neoplastic process and warrant further investigation.