Real-World Adherence to Guideline-Recommended Treatment for Small Cell Lung Cancer

Objectives: The authors sought to quantify the treatment patterns and outcomes for limited-stage (LS) and extensive-stage (ES) small cell lung cancer (SCLC) in a real-world setting. Methods: A review was conducted using the Glans-Look Research Database of patients with SCLC managed at a tertiary cancer center in Canada from 2010 to 2016. Adherence was defined as the commencement of planned SCLC treatment. Rate of compliance with the Alberta Health Services, American Society of Clinical Oncology, and National Comprehensive Cancer Network SCLC treatment guidelines was evaluated. Outcomes were analyzed using the Kaplan-Meier method and the Cox proportional hazards model. Results: A total of 404 patients met our inclusion criteria, 31% were LS. The median age at first treatment receipt was 67 years. LS treatment consisted mostly of chemoradiation (62%). Chemoradiation and surgery +/- adjuvant predicted better survival (median, 32 and 40 mo, respectively) compared with no treatment. ES treatment consisted mostly of chemotherapy (90%). Chemotherapy and thoracic radiotherapy correlated with longer overall survival (13 vs. 9 mo, respectively) compared with chemotherapy alone. Prophylactic cranial irradiation receipt in LS (50%) and ES (20%) predicted favorable survivals than none (LS: hazard ratio, 0.48; 95% CI, 0.29-0.79; ES: hazard ratio, 0.48; 95% CI, 0.33-0.70). Approximately a quarter of relapsed LS and ES had second-line chemotherapy; improved survival with second line was observed only in ES (P<0.01). Conclusions: This study highlights high rates of guideline-recommended first treatment among the real-world LS and ES patients but it also revealed important outcome differences in relapsed LS and ES patients treated with second-line chemotherapy.