Stout, Natasha K.

ABSTRACT Background Guidelines recommend primary care practitioners (“PCPs”) engage women ≥ 75 years in shared decision‐making (SDM) around mammography screening. Therefore, we aimed to develop a web‐based conversation aid about mammography screening for women ≥ 75 using output from established simulation models to provide screening outcomes based on > 23,000 combinations of individual women's health and breast cancer risk factors. Methods We used an end‐user centered design approach to develop a prototype web‐based conversation aid incorporating feedback. From July 2023 to April 2024, 10 PCPs from a Boston‐area health system and a safety‐net hospital used the prototype aid during encounters with women ≥ 75 without breast cancer or dementia ( n = 30; 1–5 patients per PCP). We observed aid use and assessed clinician effort to involve patients in SDM using OPTION5 (assesses five components of SDM, scores range 0–100). We surveyed PCPs and patients about the aid's acceptability. Patients completed the SDM‐process scale (scores range 0–4) to rate the SDM quality experienced. Participants' comments were subject to thematic analysis. Results Of 10 PCP ‐participants, seven were female and four were community‐based. Of 30 patient‐participants, 22 (73%) were non‐Hispanic White, 9 (30%) had ≥ 2 Charlson comorbidities and mean age was 78.5 years ( SD 2.8). Nine PCPs agreed that the aid helped them with SDM and was easy‐to‐use; six felt it had too much information; and seven planned to continue using the aid. Patients rated the SDM ‐process highly (scores = 3.0 [ SD 0.9]) and we observed high SDM (mean OPTION5 = 77.9 [ SD 20.6]). Participants felt the aid was “empowering” and “helpful for decision‐making.” After SDM discussions, seven patients intended to stop screening, nine to screen less frequently, and 14 to continue screening regularly. Conclusions We developed a novel conversation aid that supports SDM about mammography screening with women ≥ 75 years. Lessons learned will guide revisions of a final tool for testing in a clinical trial.

10500 Background: Inherited pathogenic variants in ATM, CHEK2, and PALB2 confer moderate to high risks of breast cancer. The optimal approach to screening in these women has not been established. Methods: We used two simulation models from the Cancer Intervention and Surveillance Modeling Network (CISNET) and data from the Cancer Risk Estimates Related to Susceptibility consortium (CARRIERS) to project lifetime breast cancer incidence and mortality in ATM, CHEK2, and PALB2 carriers. We simulated screening with annual mammography from ages 40-74 alone and with annual magnetic resonance imaging (MRI) starting at ages 40, 35, 30, and 25. Joint and separate mammography and MRI screening performance was based on published literature. Lifetime outcomes per 1,000 women were reported as means and ranges across both models. Results: Estimated risk of breast cancer by age 80 was 22% (21-23%) for ATM, 28% (26-30%) for CHEK2, and 40% (38-42%) for PALB2. Screening with MRI and mammography reduced breast cancer mortality by 52-60% across variants (Table). Compared to no screening, starting MRI at age 30 increased life years (LY)/1000 women by 501 (478-523) in ATM, 620 (587-652) in CHEK2, and 1,025 (998-1,051) in PALB2. Starting MRI at age 25 versus 30 gained 9-12 LY/1000 women with 517-518 additional false positive screens and 197-198 benign biopsies. Conclusions: For women with ATM, CHEK2, and PALB2 pathogenic variants, breast cancer screening with MRI and mammography halves breast cancer mortality. These mortality benefits are similar to those for MRI screening for BRCA1/2 mutation carriers and should inform practice guidelines.[Table: see text]