Abstract PS4-08-21: Neoadjuvant breast cancer in a real life experience in Southern of Italy

Abstract Background: Neoadjuvant therapy (NAT) is a cornerstone of breast cancer management (1). However, real-world criteria for patient selection remain poorly defined outside the context of clinical trials. A previous Italian study, which included southern regions, highlighted substantial variability in NAT utilization (2,3). According to EUSOMA, the use of NAT represents a key quality indicator within breast unit care pathways (4). This study aimed to investigate which centers in the Apulia region offer NAT, the criteria employed for patient selection, perceived barriers to its use, and the level of adherence to EUSOMA guidelines. Methods: Twelve regional Breast Units (BUs) and five of the seven spoke centers in Apulia participated in the survey (one BU did not respond). The survey was conducted between October and November 13, 2024, and analyzed data from the preceding six months. It consisted of three thematic sections: • C1: Organizational structure, multidisciplinary team (MDT) case volume, proportion of NAT-eligible cases, and the interval between the end of NAT and surgery. • C2: Proportion of NAT-eligible cases by tumor subtype (HER2+, ER/PgR+/HER2-, triple-negative). • C3: Subtype-specific barriers to NAT, with relative relevance ratings. Results: The results are described in table 1 Barriers to Neoadjuvant Therapy (NAT) Identified by Clinicians: Breast Units reports • HER2+ cases: 41% considered tumor size ≤2 cm and node-negative status (T≤2/N0) as a barrier to NAT. • ER/PgR+ cases: 100% identified T1-T2 and node-negative status (T1-T2/N0) as a limiting factor. • Triple-negative breast cancer (TNBC): 83% considered tumor size ≤1 cm as a barrier. Spokes reports: • 80% cited T≤1 cm and node-negative status (T≤1 cm/N0) as a barrier in HER2+ cases. • 100% cited T1-T2 with N0-N1 status (T1-T2/N0-1) as a limitation in ER/PgR+/HER2- cases. • 100% identified T≤1 cm/N0 as a barrier in TNBC cases. Conclusions: Although limited to a six-month period, the findings reflect the heterogeneity previously reported in broader studies. NAT rates and surgery timing were consistent with guideline recommendations, despite an unselected patient population. Tumor and nodal size—particularly in small, high-risk subtypes—emerged as key limiting factors. Spoke centers expressed greater concern about the risk of over-treatment in low-volume, high-risk scenarios. Further analyses will investigate treatment decision-making and access to clinical trials. Citation Format: M. Ciccarese, L. Orlando, F. Giotta, M. Di Millo, M. Morritti, L. Ciuffreda, S. Bambace, F. Giuliani, O. Custodero, S. Bruno, S. Stucci, M. Moschetta, S. Pisconti, G. Palmiotti, E. De Matteis, G. Cairo, S. Cinieri. Neoadjuvant breast cancer in a real life experience in Southern of Italy [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 PS4-08-21.