Abstract PO3-03-07: Patterns of Chemotherapy Utilization among Elderly Patients with Early-Stage Triple-Negative Breast Cancer
Authors: Malinowski Catalina , Lei Xiudong , Giordano Sharon , Chavez Marianna 
Published: May 2024

Background: Patterns of adjuvant and neoadjuvant chemotherapy use among patients with breast cancer have changed over time. Historically, adjuvant chemotherapy has been the standard treatment approach for patients with triple-negative breast cancer after surgical resection, aiming to eliminate any remaining cancer cells and reduce the risk of recurrence. Advancements in treatment strategies, research findings, and clinical guidelines have contributed to shifts in cancer care approaches, with an increase in the use of neoadjuvant chemotherapy. In this study, we explore chemotherapy utilization in a large cohort of elderly patients diagnosed with early-stage triple-negative breast cancer (TNBC).

Methods: Data were obtained from the SEER- and Texas Cancer Registry (TCR)-linked Medicare databases. We identified female patients aged 66 years or older, diagnosed with early-stage (localized or regional disease) TNBC between 2010 and 2017 with claims until 2019. We identified the use of chemotherapy using HCPCS codes from outpatient and physician’s carrier claims. We used descriptive statistics and analyzed overall chemotherapy utilization and time trends of neoadjuvant versus adjuvant use via the Cochran-Armitage trend test, and evaluated factors associated with chemotherapy use via logistic regression models. This study adhered to the STROBE reporting guidelines for cohort studies.

Results: Among 8,848 patients with localized or regional stage TNBC (median age 74) a total of 5,159 (58%) were treated with chemotherapy. The rate of chemotherapy utilization increased yearly from 52% in 2010 to 66% in 2017 (p&lt; 0.001). After multivariable adjustment, any chemotherapy use was associated with recent year of diagnosis (OR=1.77; 95%CI 1.54-2.04), regional stage compared to localized (OR=3.78; 95%CI 3.34-4.27), and Northeastern region compared to South (OR=1.2; 95%CI 1.06-1.37). Conversely, decreased chemotherapy use was associated with age ≥76 (OR=0.24; 95%CI 0.2-0.27), being single (OR=0.76; 95%CI 0.67-0.86), and higher comorbidity score (OR=0.69; 95%CI 0.61-0.78). Among chemotherapy-treated patients, 3,808 (73.8%) received it in the adjuvant setting, 722 (14.0%) received it in the neoadjuvant setting, and 629 (12.2%) received chemotherapy both preoperatively and postoperatively. Among those who were treated with any chemotherapy, the percentage of patients treated with neoadjuvant chemotherapy increased from 15.2% in 2010 to 37.4% in 2017 (p&lt; 0.001). Among patients treated with chemotherapy, neoadjuvant chemotherapy use was associated with recent year of diagnosis (OR=3.38; 95%CI 2.77-4.12), regional stage (OR=3.28; 95%CI 2.86-3.77), and inversely associated with older age (OR=0.77; 95%CI 0.64-0.94), non-White, non-Hispanic, non-Black race or ethnicity (OR=0.64 95%CI 0.45-0.94), non-metro area (OR=0.61; 95%CI 0.5-0.74), and Northeastern region (OR=0.66; 95%CI 0.56-0.78).

Conclusion: Our study highlights the significant changes in patterns of adjuvant and neoadjuvant chemotherapy use among elderly patients with early-stage TNBC. We observed an increasing trend in chemotherapy utilization, with a notable shift from adjuvant to neoadjuvant treatment. This transition reflects the evolving landscape of cancer care and the adoption of more personalized approaches to treatment, with increased utilization of neoadjuvant chemotherapy offering opportunities for better risk assessments and tailored treatment strategies.

Citation Format: Catalina Malinowski, Xiudong Lei, Sharon Giordano, Marianna Chavez. Patterns of Chemotherapy Utilization among Elderly Patients with Early-Stage Triple-Negative Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-03-07.