Trends, predictors, and impact of systemic chemotherapy in small cell lung cancer patients between 1985 and 2005

Abstract

Background: The last 3 decades have witnessed limited therapeutic advances in small cell lung cancer (SCLC) management. This study evaluated real-world trends in the use of systemic therapies and the impact on patient outcomes in the United States.

Methods: The Surveillance, Epidemiology, and End Results-Medicare database was used to find patients diagnosed with SCLC between 1985 and 2005. The 1985-1990 period served as the baseline for a temporal analysis conducted at 5-year intervals (1985-1990, 1991-1995, 1996-2000, and 2001-2005). Cox proportional models were used to estimate the effect of chemotherapy on survival. Results were validated with a propensity-matched analysis.

Results: There were 47,351 eligible patients: 52% were male; the median age was 71 years; and 87% were white, 7% were black, and 1.4% were Asian. The proportion of patients treated with chemotherapy was low but increased over time (38%, 55%, 50%, and 53%; P < .001). Race, diagnosis period, age, stage, and location of residence significantly predicted chemotherapy use. Females (51%), Asians (53%), and rural residents (60%) were more likely to receive chemotherapy. The median overall survival with and without chemotherapy was 9.6 and 3.6 months, respectively. Linear trend analyses showed a modest reduction in the impact of chemotherapy on survival for patients treated with chemotherapy versus untreated patients (hazard ratios [HRs], 0.59, 0.61, 0.64, and 0.62; P < .001) but an overall trend of improved survival for treated (HRs, 1.0, 1.03, 1.00, and 0.96; P = .005) and untreated patients (HRs, 1.0, 0.99, 0.94, and 0.92; P < .001). There was no survival difference between patients treated with carboplatin and patients treated with cisplatin (HR, 0.99; confidence interval [CI], 0.81-1.19; P = .875). Additional therapy beyond platinum-based chemotherapy was associated with a survival benefit (HR, 0.78; CI, 0.75-0.81; P < .001).

Conclusions: Chemotherapy use was associated with a survival benefit in Medicare patients with SCLC treated in a real-world setting.

Keywords: Medicare; Surveillance, Epidemiology, and End Results (SEER); predictors; small cell lung cancer (SCLC); survival; systemic therapy; trend analyses.