Abstract PS2-06-19: Treatment Trends in Early-Stage Breast Cancer: A Population-Based Study of Medicare Fee-For-Service Enrollees in Texas

Abstract Background: Early-stage breast cancer is typically treated with a multi-modality approach. Among older patients, concerns exist about suboptimal cancer care delivery and the possibility of greater risk of experiencing treatment delays. Since treatment delays are associated with adverse outcomes, we sought to describe patterns of care among older patients with breast cancer in Texas and estimate delays in chemotherapy administration. Methods: Using Medicare Fee-For-Service parts A, B, and D claims data, we identified individuals in Texas who underwent unilateral or bilateral mastectomy or lumpectomy from 2017 through 2020, had a breast cancer diagnosis code and had 1 year of continuous enrollment before and after surgery. Individuals with metastatic disease and malignancies of non-breast origin were excluded. Using CPT, HCPCS, and NDC codes, we developed an algorithm to identify breast cancer subtype according to treatment received. A total of 5,988 patients were identified and categorized. Among the 1,562 patients treated with chemotherapy the number of days from diagnosis to first dose of chemotherapy was estimated for patients receiving neoadjuvant chemotherapy and the number of days between surgery to chemotherapy for those treated in the adjuvant setting. Treatment delay was defined as >60 days. Descriptive statistics were reported and logistic regression models were performed to predict the odds of delaying chemotherapy. Results: Of the 5,988 individuals identified with early-stage breast cancer (HR-positive 81.5%, TNBC 11.4, HER2-positive 7.1%), median age was 72 years old [QR 69-77]. Majority (91.8%) were White and 17.6% resided in rural counties. Among those receiving chemotherapy, 32.3% received it in the neoadjuvant setting (35.9% TNBC, 34.6% HER2-positive, and 22.9% HR-positive). The median time from diagnosis to neoadjuvant chemotherapy was 34 days. For patients that received adjuvant chemotherapy, the median number of days from surgery to first dose of chemotherapy was 48 days. Overall, 24.8% of patients receiving chemotherapy experienced a delay. Among patients who received neoadjuvant chemotherapy, those living in counties with higher high-school graduation rates were significantly less likely to have a chemotherapy delay (OR=0.41, 95%CI 0.19-0.87), more comorbidities (OR=1.19 95%CI 0.99-1.41) had a borderline association with more delays. For those who received adjuvant chemotherapy, older age (OR=1.2, 95%CI 1.04-1.38), and receiving MammaPrint or Oncotype testing (OR=1.71, 95%CI 1.24-2.36), was associated with a higher likelihood of chemotherapy delay. Estimates for patients treated for TNBC and HER2-positive breast cancer suggested a lower likelihood of experiencing delays compared to those with HR-positive tumors. Conclusions: Among older individuals with early-stage breast cancer enrolled in Medicare Fee-For-Service in Texas, 24.8% of patients receiving chemotherapy experienced a delay > 60 days from either diagnosis to chemotherapy or surgery to chemotherapy. Understanding the patterns of care among older patients can provide important insights into treatment patterns and identify vulnerable patients. Citation Format: L. B. Amin, C. Shaefer, G. Cecilia, D. Allen-Benson, E. Caballero, M. Chavez-MacGregor. Treatment Trends in Early-Stage Breast Cancer: A Population-Based Study of Medicare Fee-For-Service Enrollees in Texas [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-06-19.