Effects of socioeconomic status on access to next generation sequencing in patients with metastatic breast cancer.

Abstract

1610 Background: Metastatic breast cancer is difficult to treat and a major cause of mortality related to breast cancer. Standard treatment includes therapeutic options that target specific molecular signals and pathways responsible for cancer growth. For metastatic breast cancer, focused next-generation sequencing (NGS) on DNA isolated from the tumor tissue or circulating tumor DNA in the blood has quickly become standard of care to create actionable and personalized treatment plans. In ER+ disease, NGS helps to determine potential second-line therapies. However, these tests are often expensive, limiting their clinical implementation. We hypothesized that limited access to these therapies increases health disparities in clinical oncology. Methods: Data from 187 patients with recurrent MBC were obtained from the Dallas Metastatic Breast Cancer Study, a clinical database that was established in 2021 at a single academic medical system to track patient demographics, area deprivation index (ADI), treatments, and other variables. Commercial NGS testing was performed on patient tumor tissue or tumor DNA from blood samples by Tempus and FoundationOne between the years 2014 through 2022. Results: Overall, 39% of patients in our dataset received NGS testing. Patients who are not Hispanic/Latino (n=140, OR: 3.99, 95% CI: 1.66-9.61) are 4 times more likely to receive NGS compared to those who are Hispanic/Latino. We then explored whether ADI correlated with access to NGS testing. ADI measures education level, employment, housing quality, and income to rank neighborhoods by SES disadvantage; a higher quartile ADI equates to a greater disadvantage. Our data showed that patients in the lowest quartile ADI are 2.5 times more likely to have NGS testing compared to those in the highest quartile (OR: 2.54, 95% CI 1.07-6.20). To account for different clinical indications for receiving NGS testing, we then looked at NGS trends between tumor molecular subtypes. We observed that ER+ patients were 3 times more likely to have NGS testing compared to ER- patients (n=118, OR: 2.77, 95% CI: 1.45-5.29) and that TNBC patients were less likely to receive NGS testing compared to ER+ patients, however this difference was not significant (n=113, OR: 0.36, 95% CI: 0.13-1.01). In ER+ patient population, we found that Hispanics/Latinos were 79% less likely to undergo NGS testing compared to their non-Hispanic counterparts (n=76, OR: 0.21, 95% CI: 0.06-0.73). Conclusions: These results suggest that even in clinically indicated ER+ disease, NGS testing is disproportionately offered to patients with a higher SES, particularly those who are not Hispanic/Latino. Whether these discrepancies stem from the recent adoption of NGS as standard of care or from actual barriers to accessing care should be defined in future studies. However, identifying that these disparities exist promotes awareness for clinicians to offer NGS more broadly.