Abstract PR009: Breast cancer (BC) risk reduction in young women with ductal carcinoma in situ (DCIS)

Background: Young women with DCIS are at increased risk of recurrence and second BC compared to older women and may derive the greatest benefit from risk reduction strategies. Little is known about treatment decision-making, engagement in preventive behaviors, or fear of recurrence among young DCIS survivors. Thus, we sought to investigate treatment and prevention issues in this population. Methods: Using a multicenter prospective cohort that enrolled 1302 women with stage 0-IV BC at age ≤40, we identified participants with DCIS only who completed surveys in the year following diagnosis (dx). Surveys assessed treatment decisions, lifestyle factors (alcohol, smoking, physical activity [PA]), and fear of recurrence (Lasry Scale). Data was summarized with descriptive statistics and groups were compared with Fisher’s exact test. Results: Among 87 patients (median age 38, range 26-40), 75 had available treatment decision data, 19 (25%) of whom had breast-conserving surgery (BCS), 11 (15%) unilateral mastectomy (UM), and 45 (60%) bilateral mastectomy (BM). Most (77%) indicated their doctor said BCS was an option or recommended, including 34 (59%) who had BM. Of 40 patients who reported a patient-driven surgical decision, 73% had BM, 13% UM, and 15% BCS. Among 15 patients who reported the decision as doctor-driven, none had BM, 27% UM, and 73% BCS. Those who had BM were more likely to be extremely confident about the decision (80% vs. 73% UM vs. 53% BCS, p=0.022). Adjuvant tamoxifen was used by 10/27 (37%) patients with ER+ DCIS who had BCS/UM. Most who took tamoxifen reported this decision was shared with their doctor (90%); 1 reported the decision was made on her own. Of the 17 patients who did not take tamoxifen, 88% indicated their doctor said endocrine therapy was an option or recommended. Among all 87 patients, 31 (36%) were former and 3 (4%) were current smokers at baseline assessment (median 5 months post-dx); 51 (59%) never smoked. Overall, 4 quit within 1 year of dx. Most patients (83%) were current drinkers at baseline, though 79% consumed