Impact of racial disparities in adjuvant treatment of triple negative breast cancer (TNBC) among American Indians/Alaskan Natives (AI/AN) and non-Hispanic Whites (NHW) on overall survival (OS).
Authors: Anu G. Gaba, Li Cao, Rebecca Renfrew, Abe Eric Sahmoun, Sanjay Goel, Ross Crosby
Journal: Journal of Clinical Oncology (2024)

e13736 Background: There are significant differences in patient and tumor characteristics among AI/AN and NHW breast cancers (BC) which adversely impact overall survival in AI/AN. Prior studies have also shown higher Mortality: Incidence ratio for BCs in AI/AN as compared to NHW. The aims of this study are to 1) investigate disparities in adjuvant treatment of TNBC between the two races adjusting for age, stage, and year of diagnosis; and 2) Assess differences in OS. Methods: This was a hospital based, retrospective cohort study using the National Cancer Database. AI/AN and NHW women with TNBC, greater than or equal to 18 years of age, diagnosed with BC between the years 2010 through 2019, stages I, II, and III were included. Propensity score matching in a 1:3 ratio was used for age, year, and analytical stage at diagnosis. Primary endpoint was time to first treatment and compliance with recommended treatment. Secondary endpoint was OS. Results: A total of 489 AI/AN and 1465 matched NHW women with TNBC were identified. AI/AN women traveled longer distances for cancer care (p&lt;.01), resided in lower median income zip codes at the time of diagnosis (p&lt;.001), had a higher Charlson-Deyo (CD) comorbidity score (p&lt;.001), and were less likely to have private insurance (p&lt;.001). There was no difference in the rates of chemotherapy, surgery, and radiation therapies that were recommended and received by the two races. Time to first treatment was significantly longer for AI/AN as compared to NHW women (Mean ± SD: 35 ± 27 days vs. 39 ±27 days; p=.005). Multivariable analysis revealed that longer time to first treatment was associated with only higher CD score (p=.013) and non-private insurance (p=.027), but no longer associated with race (p=.324). Compliance with recommended treatment was similar between AI/AN and NHW women (93.5% vs 92.9%, p=.096). Compliance was significantly associated with only insurance status (p &lt; .001) with Medicare/Medicaid having the lowest compliance. OS did not differ by race (p=.299, HR=1.132; 95% CI: 0.90-1.43). Cancer stage, CD score, insurance status, and treatment compliance were associated with worse OS. Conclusions: In patients with TNBC, there was no difference in time to treatment, compliance with recommended treatment or OS among AI/AN in comparison to White women when matched for age, stage, and year of diagnosis. Medicare/Medicaid insurance was associated with prolonged time to treatment, lower compliance with recommended treatment and decreased survival when compared with other insurances. Higher comorbidities adversely impacted time to treatment and overall survival. In order to improve BC mortality, it is important to manage comorbid conditions and improve detection of cancer at earlier stages. Prospective studies comparing outcomes by race are needed to confirm these findings.