Abstract Background: Breast cancer (BC) treatment is increasingly complex, with a strong need for coordinated decision-making among specialists within multidisciplinary teams (MDTs). Despite their critical role in optimizing patient care, limited data exist on the structure and functioning of BC MDTs in Portugal. To address this gap, the PRISMA study collected both qualitative and quantitative data to characterize the organization, composition, and operational practices of BC MDT meetings across various regions and healthcare sectors nationwide. Methods: A mixed-methods approach was used to analyze multidisciplinary team practices from January 2022 to June 2023. For qualitative data, a Delphi methodology was applied through a questionnaire developed from a systematic literature review. Sixty-four Portuguese specialists involved in BC MDT meetings during this period were invited to participate. Two rounds of anonymous online voting were conducted from October 2024 to December 2024, using a five-point Linkert scale; consensus was defined as ≥ 80% concordance among responses. For the quantitative data, retrospective aggregated information from MDT meetings were collected. Results: Forty-six specialists from 13 Portuguese centers participated in the Delphi panel, including representatives from 3 cancer institutes, 3 university hospitals, and 9 general hospitals, encompassing the private (3 centers) and public (10 centers) healthcare sectors. Ten centers also participated in the quantitative phase of the study, where MDT meetings have been held for an average of 18 years. During the study period, each center held an average of 88 meetings, with each meeting lasting approximately 2.3 hours. Most teams had 5-10 members (70%), including medical oncologists (100%), breast surgeons (100%), radiologists (90%), radiation oncologists (90%), pathologists (70%), and oncology nurses (60%). Additional medical and other specialties represented in at least one center included gynecology, nuclear medicine, social service, geriatrics, and data managers. These findings were validated by the Delphi panel, which underscored the role of specialized MDTs with core and supplementary members. During the study period, most meetings were conducted in a hybrid format (60%), with presential (40%) and virtual (30%) formats also reported. On average, 15 cases were discussed per meeting, totaling approximately 767 annually. Of these, on average 45 cases were revised, mainly due to missing prior information (70%). Experts participating in the Delphi panel considered MDT meetings crucial for delivering evidence-based, personalized treatment and minimizing patient care disparities. Key challenges identified included time constraints, delays in diagnosis and staging procedures, and staff shortages. Conclusions: MDT meetings are well established in Portuguese centers and align with international recommendations. This study, through a mixed-methods approach, identified both strengths and operational challenges in MDT practices. Experts emphasize their critical role in ensuring evidence-based, patient-centered care. Findings support efforts to standardize and strengthen MDT functioning to ensure high-quality breast cancer care nationwide. Citation Format: G. Sousa, A. M. Ferreira, I. Pereira, C. Abreu, D. Simão, F. Machado, G. Fernandes, R. A. Leonor, J. Fougo, M. C. Nogueira, P. H. Meireles, J. Abreu Sousa, P. F. Cortes. Multidisciplinary Team Decision-Making in Breast Cancer: Real-World Insights from the PRISMA Study 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 PS5-11-05.
Sousa et al. (Tue,) studied this question.