The Influence of Sex and Histology on Outcomes in Non-small-cell Lung Cancer: a Pooled Analysis of Five Randomized Trials

Background: Some non-small-cell lung cancer (NSCLC) surgical series have indicated that the positive prognostic effect of female sex is limited to patients with adenocarcinoma. We carried out a retrospective analysis to investigate the role of sex and histology on efficacy, toxicity, and dose delivery after chemotherapy.

Patient And Methods: Individual patient data were pooled from five randomized, phase III, advanced NSCLC chemotherapy trials. Primary outcomes were response rate, overall survival (OS), toxicity, and dose delivery. A secondary analysis examined survival by sex in histological subgroups.

Results: Of 2349 patients, 34% were women. Women had a higher response rate to chemotherapy (42% versus 40%, P = 0.01) and longer survival than men (median OS 9.6 versus 8.6 months, P = 0.002). The difference in OS remained after adjusting for age, stage, performance status, and histology (hazard ratio 0.83, 95% confidence interval 0.74-0.92, P = 0.0005). Upon further examination, longer survival in women was only seen in patients with adenocarcinoma (test for interaction P = 0.006). There were no differences in hematological toxicity or transfusions. Women experienced more grade 3-4 emesis than men (P < 0.0001) and more dose delays (P = 0.02) or dose reductions (P < 0.0001).

Conclusion: The positive prognostic effect among women is confirmed in patients receiving platinum-based chemotherapy but appears confined to those with adenocarcinoma histology.