Effects of Chemotherapy on Survival of Elderly Patients with Small-Cell Lung Cancer Analysis of the SEER-Medicare Database

Introduction: This retrospective cohort study was designed to analyze factors associated with administration of chemotherapy and to examine the impact of chemotherapy on survival among elderly patients with small-cell lung cancer (SCLC) in the community. Methods: Elderly patients aged 65 years and older with SCLC diagnosed between 1992 and 2001 were selected from the Surveillance, Epidemiology, and End Results-Medicare database. Logistic regression was used to evaluate which covariates influenced receipt of chemotherapy. Cox proportional hazards regression was used to examine the influence of clinical and demographic variables on survival. The independent effect of chemotherapy on survival was determined using propensity scores and quantile regression. Results: In the final cohort of 10,428 patients, 67.1% received chemotherapy, 39.1% received radiation, 3.4% received surgery, and 21.8% received no treatment. The most common chemotherapy regimens included etoposide combined with either cisplatin or carboplatin. Patients aged 85 years and older were significantly less likely to receive chemotherapy compared with patients aged 65 to 69 years (odds ratio 0.17; 95% confidence interval 0.14-0.21). Median survival for all patients was 7 months. Factors associated with improved survival were being female, black race, having limited-stage disease, receiving any treatment, and having a lower comorbidity score. Quantile regression demonstrated that chemotherapy provided a 6.5-month improvement in median survival (95% confidence interval 6.3-6.6; p<0.001). Conclusions: Statistically significant differences in the receipt of chemotherapy exist among elderly patients with SCLC. Chemotherapy is associated with a greater than 6-month improvement in median survival among elderly patients with SCLC, even in patients over the age of 80 years.