Disparities and Trends in Genetic Testing and Erlotinib Treatment among Metastatic Non-Small Cell Lung Cancer Patients.

Background: 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 such disparities are changing over time.

Methods: 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 patients with stage IV NSCLC diagnosed in 2007 to 2011 at age 65 or older. We performed logistic regression analyses to identify patient factors associated with odds of receiving a genetic test and erlotinib treatment, and to assess trends in these differences with respect to diagnosis year.

Results: Patients were more likely to receive genetic testing if they were under age 75 at diagnosis [odds ratio (OR), 1.55] independent of comorbidity level, and this age-based gap showed a decrease over time (OR, 0.93). For untested patients, erlotinib treatment was associated with race (OR, 0.58, black vs. white; OR, 2.45, Asian vs. white), and was more likely among female patients (OR, 1.45); for tested patients, erlotinib treatment was less likely among low-income patients (OR, 0.32). Most of these associations persisted or increased in magnitude.

Conclusions: Race and sex are associated with rates of erlotinib treatment for patients who did not receive genetic testing, and low-income status is associated with treatment rates for those who did receive testing. The racial disparity remained stable over time, while the income-based disparity grew larger.

Impact: Attention to reducing disparities is needed as precision cancer treatments continue to be developed.