Current treatment patterns for early breast cancer among healthcare professionals and concordance with expert recommendations: Analysis of an online interactive decision support tool.

1550 Background: The treatment paradigm for HER2-negative early breast cancer (EBC) now includes pembrolizumab and targeted therapies such as olaparib, abemaciclib, and most recently, ribociclib in the adjuvant setting for eligible patients. Here, we assess current intended treatment patterns among healthcare professionals (HCPs) for EBC and compare them with those of experts using an online Interactive Decision Support Tool (IDST). Methods: We developed an online IDST in July 2024 with input from 5 breast cancer experts providing therapy recommendations for 12 unique patient case scenarios based on presentation characteristics including disease subtype, disease burden, treatment history, BRCA mutation status, and risk of recurrence. HCPs entered specific patient characteristics to define a case along with their intended management for that case. The IDST then showed each expert’s recommendation for that case scenario and asked the HCPs if the recommendations affected their intended approach. Here, we report a comparison of the expert recommendations and HCP-selected therapy for different EBC case scenarios. Results: Between August 2024 and January 2025, 140 HCPs entered 182 cases. Among the 138 HCPs who indicated their treatment plan, plans were concordant with experts for 59% of the cases. Of note, the 5 experts showed complete concordance in their treatment recommendations for all 12 unique case scenarios. Concordance with the experts was higher among HCP treatment plans for cases of hormone receptor–positive (HR+)/HER2-negative (HER2-) cases compared with triple-negative cases (65% vs 49%). High concordance was seen for HR+/HER2- cases receiving adjuvant AI with BRCA WT and high risk of recurrence per the monarchE trial criteria (86%; n = 37) with lower concordance for this setting without a high risk of recurrence (65%, n = 26) with HCPs often choosing endocrine therapy plus a CDK4/6 inhibitor. In the setting of TNBC, HCPs entered cases predominantly related to adjuvant therapy after neoadjuvant chemotherapy plus pembrolizumab (n = 44). Among cases without a pathologic CR in this setting (n = 29), concordance was 50% with or 54% without a pathologic germline BRCA variant, respectively. Among TNBC cases with a pathologic CR in this setting (n = 15), concordance was 40% with overtreatment by HCPs evident in 33% of cases. HCPs indicated that expert recommendations changed their intended treatment in 28 of 84 (33%) cases and confirmed their choice in 45 of 84 cases (53%). Conclusions: These data suggest ongoing challenges with incorporating pembrolizumab and the newest targeted therapies into adjuvant treatment plans for high-risk EBC, particularly TNBC. Continued education and development of resources for HCPs, including online IDSTs, may be increasingly important as the treatment of high-risk EBC continues to evolve.