Abstract PS5-04-06: Current and Emerging Treatment Patterns for Patients with Residual Disease Post-Neoadjuvant Therapy in Early-Stage Triple Receptor-Negative Breast Cancer

Abstract Background: Triple-negative breast cancer (TNBC) is associated with a poorer prognosis compared to other subtypes. Neoadjuvant chemotherapy with anthracyclines and taxanes aims to improve pathological complete response (pCR) rates. Patients without pCR face higher relapse risks and worse outcomes, necessitating escalation strategies for residual disease. Objective: This review aimed to summarize real-world treatment patterns for patients with early-stage TNBC focusing on adjuvant therapy for those with residual disease after neoadjuvant chemotherapy. Methods: A systematic literature search was conducted using Embase and MEDLINE databases (2014-2024) and relevant conference proceedings (2021-2024). Real-world studies on treatment utilization rates, discontinuation rates, efficacy, and safety were included. Results: Six studies from the USA, Brazil, Italy, Turkey, and Middle East Africa region were identified. Capecitabine alone or in combination with radiotherapy emerged as the primary adjuvant pharmacological therapy for residual TNBC after neoadjuvant chemotherapy. This was reported in three studies, with utilization rates ranging from 31.7% to 42.1%. Additionally, adjuvant radiotherapy was reported in two studies, with higher usage rates ranging from 71.1% to 94.7%. Most patients received sequential rather than concurrent radiotherapy and capecitabine treatment. The rates of discontinuation varied by cause, with toxicity accounting for 6.0% to 17.0% of discontinuations and disease progression leading to 12.6% to 17.0% of discontinuations. Two-year disease-free survival (DFS) rates after adjuvant capecitabine ranged from 62.0% to 88.9%. The three-year overall survival (OS) rate for patients with residual disease treated with adjuvant capecitabine, either alone or in combination with radiotherapy, was 76.2%. The proportion of patients experiencing disease progression (PD) after adjuvant therapy ranged from 28.9% to 64.2%. Conclusion: This review highlights significant unmet needs in early TNBC patients with residual disease after neoadjuvant therapy. While guidelines recommend capecitabine for this patient population, they also recommend exploring newer therapies like pembrolizumab and olaparib for specific patient sub-populations. There are treatment strategies available for the peri-operative setting, but the associated evidence was not captured in this review. The high rates of residual disease, treatment discontinuation, and disease progression underscore the need for more effective and tolerable adjuvant therapies. Currently, multiple novel therapies are being evaluated for this patient population including antibody drug conjugates (ADCs) and other targeted immunotherapies to improve outcomes and mitigate the unmet need. Citation Format: A. Haiderali, J. R. Earla, P. Kondaparthi, J. Nathani, S. Sharma. Current and Emerging Treatment Patterns for Patients with Residual Disease Post-Neoadjuvant Therapy in Early-Stage Triple Receptor-Negative Breast Cancer [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 PS5-04-06.