Abstract P3-05-05: Racial disparities among patients with breast cancer receiving neoadjuvant chemotherapy therapy and impact on pathologic response: An urban, single-institution experience
Authors: Chacko Rebecca , Abdel-Razeq Nayef Hikmat , Shango Kathren , Li Pin , Dabak Vrushali , Ali Haythem 
Published: March 2023

Background: Neoadjuvant systemic therapy (NAT) is typically administered to patients diagnosed with non-metastatic invasive breast cancer (IBC) with high-risk features. The goal of NAT in this setting is a pathologic complete response (pCR), meaning no residual invasive disease observed on final review of surgical pathology. It is broadly accepted that pCR may be used as a surrogate marker of predicted long term benefit of treatment and overall survival. Prior studies have demonstrated that the time interval between a diagnosis and initiating NAT may impact the overall outcome for patients.

In this study we sought to determine if there were any differences between African American (AA) patients and other races with respect to time-to-treatment (TTT) in initiating NAT. In addition, we explored the relationship between TTT and pCR rates and the factors influencing this relationship.

Methods: This is a single-institution retrospective study, all patients diagnosed with non-metastatic IBC who were treated with NAT and completed definitive surgery between 2015-2021 were included. Demographic and clinicopathologic details were abstracted from the electronic medical record. Data was analyzed in aggregate; subgroup analysis was completed according to race and histopathologic subtype of breast cancer.

Results: A total of 392 female patients were included in this study: 59.2% White, 35.7% AA, 5.1% were of other races. The average age at the time of diagnosis was 54.1 ± 13.4 years old for the total population, and 54.0 ± 13.0 years old for AA patients. Mean TTT was 33.4 (SD = 18.7) days for all patients, 37.0 (SD = 21.3) days for AA patients and 31.3 (SD = 16.9) days for White patients. A significant difference was identified in AA patients versus the total population (p=0.017), and particularly AA versus White patients (p=0.005). A pCR was achieved in 40.7% of AA patients and 34.7% in the total population (p=0.050). Multivariate analysis of the factors impacting the pCR rate showed that TTT, age, tumor grade and histologic subtype independently influenced the pCR rate. However, race was not an independent factor. Among the studied factors influencing pCR rate only TTT is modifiable (Table 1).

Conclusion: The results of our study show that although AA patients achieve pCR at higher rates than the general population, they do experience delays in TTT which is an independent factor influencing pCR rates. Other factors inherently play a role in achieving a pCR, however, race is not one of them. pCR rates among AA patients may be further improved by reducing TTT and maximizing the potential benefit of neoadjuvant systemic therapy.

Table 1: Association between TTT, race, pCR. Table 1 depicts the demographic distribution related to the mean time-to-treatment (TTT), total population and percentage of Black patients. Data was analyzed as an aggregate and subgroup analyses were conducted according to histologic subtypes. Multivariate analyses were used to explore the association between TTT and pathologic complete response (pCR). HR+=Estrogen/progesterone receptor positive; HER2+= human epidermal growth factor receptor 2 (HER2) present by IHC 3+ score or FISH ≥2 ratio; TNC=triple negative cancer. Indicates a statistically significant finding (i.e.: p=&lt;0.05).

Citation Format: Rebecca Chacko, Nayef Hikmat Abdel-Razeq, Kathren Shango, Pin Li, Vrushali Dabak, Haythem Ali. Racial disparities among patients with breast cancer receiving neoadjuvant chemotherapy therapy and impact on pathologic response: An urban, single-institution experience [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-05.