Despite reports of socioeconomic disparities in rates of genetic testing and targeted therapy treatment for metastatic non-small cell lung cancer (NSCLC), little is known about whether and how such disparities change over time in the context of the rapidly evolving field of precision cancer treatment. We performed a retrospective analysis to identify disparities and trends in genetic testing and treatment with erlotinib. Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified 9,900 stage 4 NSCLC patients diagnosed in 2007-2011 at age 65 or older and used procedural codes to identify receipt of a genetic test and Medicare Part D records to identify erlotinib treatment. We performed multivariate logistic regression analyses to identify patient factors associated with differences in odds of receiving a genetic test and in receiving erlotinib treatment, and to assess temporal trends in these differences with respect to diagnosis year. We considered socioeconomic, clinical, and demographic patient factors, as well as whether any gaps due to these factors grew, narrowed, or stayed the same. We found that patients were more likely to receive genetic testing if they were under age 75 at diagnosis (odds ratio [OR]=1.58, 95% confidence interval [CI] 1.23 to 2.05) or had adenocarcinoma (OR=1.58, 95% CI 1.20 to 2.09); odds also grew with later year of diagnosis (OR=2.14, 95% CI 1.78 to 2.56). Patients with low income level were less likely to receive genetic testing (OR=0.72, 95% CI 0.53 to 0.99). Only the odds associated with being under 75 at diagnosis showed change (a decrease) over time (OR=0.93, 95% CI 0.87 to 0.99). Erlotinib treatment was associated with race (OR=0.58, 95% CI 0.36 to 0.94 for black vs. white; OR=2.44, 95% CI 1.54 to 3.88 for Asian vs. white), was more likely among female patients (OR=1.38, 95% CI 1.19 to 1.59) and those with adenocarcinoma (OR=1.19, 95% CI 1.03 to 1.38), and was less likely among low-income patients (OR=0.79, 95% CI 0.67 to 0.93). All of these associations persisted throughout the study time period. Our results demonstrate that low socioeconomic status is the only nonclinical patient factor that independently predicts lower rates of both genetic testing and erlotinib treatment, and this disparity has remained steady over time. This finding suggests that more attention to closing this socioeconomic gap is needed as precision cancer treatments continue to be developed and refined.

Citation Format: Lauren Palazzo, Deirdre Sheehan, Angela Tramontano, Chung Yin Kong. Disparities and trends in genetic testing and erlotinib treatment among metastatic non-small cell lung cancer patients [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B087.

©2020 American Association for Cancer Research.
2020
American Association for Cancer Research.