Abstract PS1-02-01: Knowledge, risk perception, and decision making in patients with a history of ductal carcinoma in situ (DCIS) or atypical breast lesions: a secondary analysis from the PORTAL Study

Abstract Background: The COMET trial demonstrated that active monitoring (AM) is not inferior to guideline concordant care (GCC) in patients with low-risk ductal carcinoma in situ (DCIS), with comparable rates of ipsilateral invasive breast cancer (iBC) and quality of life outcomes. Similarly, patients with atypical breast lesions have an increased risk of iBC and are managed with an AM strategy which could serve as a proxy for future omission of surgery in low-risk DCIS. Acknowledging that acceptance of treatment deintensification is likely linked to patient preferences, understanding, and risk perception, this analysis assessed these patient-reported outcomes (PROs) among patients with atypical breast lesions and DCIS. Methods: In this secondary analysis of the Patient-reported Outcomes after Routine Treatment of Atypical Lesions (PORTAL) Study - a multicenter cross-sectional survey study - we compared PROs from women with DCIS who received GCC, to women with high-risk breast lesions (e.g., atypical ductal hyperplasia [ADH], lobular intraepithelial neoplasia [LIN]) who underwent AM. We report on participants’ fear of invasive breast cancer (using Quality of Life in Adult Cancer Survivors [QLACS]), and disease understanding and decision quality (using Breast Cancer Surgery Decision Quality Instrument-Sections 1 and 3 [BCS-DQI-S1/3], SURE scale, Decision Regret Scale [DRS]; and Control Preferences Scale [CPS]). Descriptive statistics were provided, with means and standard deviations (SD), or proportions and 95% confidence intervals (CI). Results: 903 patients were included: 538 underwent GCC for DCIS; 365 underwent AM for ADH/LIN (Table). The mean QLACS score was 1.9/4 in both groups, indicating low to moderate fear of developing iBC, with minimal impact on quality of life. The mean knowledge of the natural history of breast lesions was 77% of patients in the DCIS group and 67% in the ADH/LIN group. In the DCIS group, 84% of patients received treatment aligned with their personal goals (concordance score, BCS-DQI-S1). Mean Decision Process Scores (BCS-DQI-S3) were 77% and 63%, respectively, indicating a high level of shared decision-making. According to the CPS, 61% of patients reported a collaborative role in decision-making. On average, there was low or no regret about treatment decision (DRSs were 12/100 and 10/100). Among patients with DCIS, 81% reported no decisional conflict (SURE scale). Conclusions: These findings suggest that women with ADH/LIN and DCIS report high levels of knowledge, goal-concordant care, and involvement in shared decision-making, potentially suggesting that AM is acceptable and presents a future opportunity to de-intensify treatment for low-risk DCIS, pending results of clinical trials. Citation Format: C. Valenza, S. M. Rosenberg, K. Crowell, K. L. Schreiber, I. Bedrosian, K. S. Hughes, T. Lynch, D. Basila, D. Collyar, E. S. Frank, S. Darai, C. Lanahan, J. R. Marks, J. K. Plichta, A. M. Thompson, T. Hyslop, S. Hwang, A. H. Partridge. Knowledge, risk perception, and decision making in patients with a history of ductal carcinoma in situ (DCIS) or atypical breast lesions: a secondary analysis from the PORTAL 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 PS1-02-01.