Abstract P2-09-08: Impact of race on clinical outcomes among patients with advanced triple negative breast cancer (TNBC) and Germline BRCA1/2 mutation(s) (gBRCA1/2mut): Results from a US real-world study
Authors: Whitaker Kristen , Parikh Rohan , Esterberg Elizabeth , Arondekar Bhakti , Hitchens Abigail , Arruda Lillian Shahied , Niyazov Alexander , Obeid Elias 
Published: March 2022

Background: Racial disparities among patients with breast cancer in the United States are well documented, with Black patients having a 40% higher mortality than White patients. Socioeconomic status, tumor biology differences, and treatment access are known contributing factors. Additionally, despite having a higher incidence of TNBC, Black patients are substantially less likely to receive gBRCA1/2mut testing than White patients. TNBC is an aggressive subtype, accounting for 15% of all breast cancers diagnosed in the United States. TNBC disproportionately affects BRCA mutation carriers and Black women. With the advent of poly ADP-ribose polymerases inhibitors (PARPi), gBRCA1/2mut are considered actionable biomarkers. Limited data are available on the impact of race on clinical outcomes among patients with gBRCA1/2-mutated advanced TNBC in the United States. Methods: US oncologists retrospectively reviewed patient charts (July 2019-June 2020) of a quasirandom selection of patients aged ≥18 years with gBRCA1/2-mutated advanced TNBC who received ≥1 cytotoxic chemotherapy (CT) regimen for advanced TNBC between Jan 2013-April 2018. Patients were categorized into 2 mutually exclusive cohorts of White and Black (based on self-identification). Descriptive analysis was performed for treatment patterns for the first 2 lines of therapy (LOT). Clinical outcomes (progression-free survival [PFS] by LOT and survival rates) were estimated with the Kaplan-Meier method. A log-rank test was used to assess differences in PFS and survival rates between White and Black patients. Results: Among 182 patients with gBRCA1/2-mutated advanced TNBC, 99.5% were women and 76.4% were White. The median age was 57.2 years (range, 48.7-64.7 years), and 30.2% had no known family history of BRCA-related cancer. Treatments for White patients with advanced TNBC included first-line (n=139) nonplatinum-based CT (61.9%) and platinum-based CT (38.1%) and second-line (n=90) PARPi (40.0%), nonplatinum-based CT (43.3%), platinum-based CT (11.1%), and other (5.6%). Treatments for Black patients with advanced TNBC included first-line (n=43) nonplatinum-based CT (60.5%) and platinum-based CT (39.5%) and second-line (n=19) PARPi (47.4%), nonplatinum-based CT (31.6%), platinum-based CT (10.5%), and other (10.5%). Across treatment types, no significant difference in 2-year survival rates was observed between White and Black patients (73.8% vs 73.2%, P=0.89). Median PFS rates by LOT were not statistically different across White and Black patients (Table 1). Conclusion: In this real-world study, no significant differences in clinical outcomes were observed between White and Black patients with gBRCA1/2-mutated advanced TNBC. This observation may be because this sample reflects a select patient population with a known genetic test result of a gBRCA1/2mut who were treated by oncologists that understood the value of genetic testing, and provided appropriate treatment options. The findings suggest that when all patients are provided with equitable care (inclusive of genetic testing), racial disparities in breast cancer may be minimized. Further trials are needed to validate these findings. Funding: Pfizer Inc

Table 1.PFS (Months) by LOT and Race Among Patients With gBRCA1/2-Mutated Advanced TNBCWhite PatientsBlack PatientsP ValueFirst-line, n 13642PFS, median (95% CI)10.7 (9.3−12.6)15.6 (9.7−NE)0.078Second-line, n 5310PFS, median (95% CI)7.2 (5.9−11.4)9.2 (2.8−NE)0.406NE=not estimatable.

Citation Format: Kristen Whitaker, Rohan Parikh, Elizabeth Esterberg, Bhakti Arondekar, Abigail Hitchens, Lillian Shahied Arruda, Alexander Niyazov, Elias Obeid. Impact of race on clinical outcomes among patients with advanced triple negative breast cancer (TNBC) and Germline BRCA1/2 mutation(s) (gBRCA1/2mut): Results from a US real-world study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-09-08.