Patient characteristics and outcomes associated with small cell lung cancer by treatment status in a U.S. Medicare population.

Abstract

e20614 Background: Globally, small cell lung cancer (SCLC) accounts for approximately 10% of lung cancers and is typically diagnosed at an advanced/extensive stage in elderly current or former smokers. The objective of this study was to describe patient characteristics (demographic and clinical) and outcomes (survival) associated with SCLC in the Medicare population by systemic anticancer treatment status (treated vs untreated). Methods: A retrospective analysis was conducted using the Surveillance, Epidemiology, and End Results (SEER)–Medicare linked database. Patients were included if they had a record with a diagnosis of SCLC in the database from 1/1/2007 – 12/31/2017, were ≥65 years of age at diagnosis, and had continuous enrollment for ≥180 days pre-SCLC diagnosis. Patient characteristics and overall survival (OS) were stratified by treatment status. Median OS was estimated using the Kaplan Meier method. Results: 13,516 patients met the study criteria. Overall, 57.7% were female, mean age was 74 years, and 89.5% were white. Nearly three-fourths (73.1%) were diagnosed with stage 4 disease. Just over half (55.4%, N = 6,022) initiated 1L treatment. Older patients were less likely to be treated: 36.3%, 51.1%, and 78.5% of patients 65-74 yrs, 75-84 yrs, and 85+ yrs, respectively, were untreated. Patients diagnosed at stage I-III were more likely to be treated than those diagnosed with stage IV disease (68.2% vs 51.4% treated). Patients with metastasis in the brain and/or liver were also less likely to be treated than patients without metastasis in those sites. On average untreated patients had more comorbid conditions than treated patients (average Charlson Comorbidity Index [CCI] 9.2 vs 9.5). In particular, congestive heart failure (49.3% vs 32.6%), myocardial infarction (25.7% vs 18.9%), renal disease (31.5% vs 18.9%), dementia (13.3% vs 3.5%), hemiplegia/paraplegia (8.0% vs 3.2%), and diabetes with complications (21.1% vs 16.4%) were more common among untreated patients. Median survival among untreated patients was 1.1 months (95% CI: not estimable) versus 9.2 months (95% CI:9.0-9.5 months) among treated patients. Approximately 5% of untreated patients were alive 12 months after diagnosis whereas 40% of treated patients were alive 12 months after initiating 1L treatment. Conclusions: Nearly half of SCLC patients did not initiate systemic anticancer treatment. Those who were untreated were on average older, had more comorbid conditions, were more likely to be diagnosed with stage IV disease, and had shorter survival, affirming the continued need for safe and effective therapies for SCLC.