Analyzing the Gaps in Breast Cancer Diagnostics in Poland—A Retrospective Observational Study in the Data Donation Model

<b>Background:</b> Breast cancer is a major health concern in Poland, with significant incidence and mortality rates despite national screening programs. This retrospective study aimed to evaluate critical aspects of breast cancer management, focusing on waiting times, treatment coordination, cancer characteristics, diagnostic testing, and staging. <b>Methods:</b> We retrospectively analyzed 587 medical records of breast cancer patients (585 female, 2 male) collected between March 2023 and June 2024 through a data donation model. Data included tumor characteristics (histological type, grade, stage, biological subtype, receptor status, Ki-67), diagnostic and genetic tests, and timelines of key events in the diagnostic and therapeutic pathways. <b>Results:</b> Although referral to first oncology consult (18 days) and MDT referral/admission to treatment (10 days) met NFZ guidelines, diagnosis to surgery (94 days) and diagnosis to drug treatment (109 days) were significantly delayed. No records showed oncology coordinator assignment or educational material provision. Clinically, invasive carcinoma NST (77%) and early-stage (IA/IIA, 61%) were prevalent, with Luminal B (HER2-negative) being the most common biological subtype. BRCA1/2 testing was common, but Oncotype DX was not. For 314 HR+ HER2- patients, stage IA (44%) was most common, with no BRCA1/2 mutations found. <b>Conclusion:</b> Breast cancer care in the Łódź voivodeship falls short of national guidelines due to long waiting times and poor care coordination, a problem worsened by incomplete data. Improving record-keeping and speeding up diagnostic and treatment pathways are crucial for better breast cancer management in Poland. While patient data donation can help analyze real clinical pathways, data completeness, and consistency remain challenges.