Sex differences in survival in non-small cell lung cancer patients 1974–1998

Abstract

This study comprised a total of 7 553 patients with non-small cell lung cancer (2 660 women and 4 893 men) treated at a comprehensive cancer centre between 1974 and 1998. Significant differences in tumour histology were associated with gender (p<0.001); adenocarcinoma was the most common diagnosis in both men (50.0%) and women (41.7%); squamous cell carcinoma was the second most prevalent diagnosis (21% and 31% in women and men, respectively); and bronchioalveolar tumours were more prevalent in men (3% compared with 7% in women). Frequency distributions with local, regional or distant disease at registration were similar between men and women (p=0.906). In a multivariable Cox regression analysis the indications were that gender is an important risk factor for survival. Adjusting for age, stage, treatment received and ability to pay for care, a statistically significant interaction between gender and tumour histology (p=0.043) was found, where, in relation to female sex and histologies other than squamous carcinoma, women who presented with squamous carcinoma had an increased risk of death (HR=1.09, 95% CI 1.02–1.18) while men had an increased risk of death for all histologies (HR=1.29, 95% CI 1.21–1.40, and HR=1.15, 95% CI 1.07–1.24 for squamous and other histologies, respectively). This study confirms previous reports of strong gender-dependent differences in survival in patients with non-small cell lung cancer, including a histology-specific effect in women.