Is sex associated with the outcome of patients treated with radiation for nonsmall cell lung cancer?

BACKGROUND: Lung cancer is the leading cause of cancer death for both men and women, but the disease course differs between the sexes. To the authors' knowledge, sex-based differences in outcomes among the population of nonsmall cell lung cancer (NSCLC) patients receiving radiation have not been well defined. METHODS: Data for 831 patients (319 women and 512 men) with stage I to III NSCLC and treated with ≥45 Gray of radiation between March 1985 and November 2003 were retrospectively analyzed (grading determined according to the 1997 American Joint Committee on Cancer grading system). RESULTS: Women were more likely to have earlier stage disease, to have smoked <50 pack-years, and to have adenocarcinoma or large-cell carcinoma (all P ≤ .001). For each stage, treatment did not differ between women and men. Five-year survival rates were significantly better for women than for men: overall survival (OS), 28.6% versus 16.1% (P < .001); disease-free survival, 31.2% versus 20.1% (P = .02); and distant metastasis-free survival, 48.8% versus 37.6% (P < .02). Among patients with medically inoperable stage I NSCLC, women had improved 5-year OS compared with men (30.0% vs 13.1%; P = .004). On multivariate analysis, male sex, weight loss, age ≥65 years, and stage III disease were found to be associated with poorer OS (all P < 0.02). CONCLUSIONS: Although women are more likely to have earlier stage disease, among patients with medically inoperable stage I NSCLC, women still have a better OS. Along with known prognostic factors, including age, weight loss, and stage, sex remained significant on multivariate analysis of OS, suggesting that sex is a determinant of outcome in NSCLC patients receiving radiation.