Abstract P2-12-01: Patient attitudes, experience and results of screening for minimal residual disease (MRD) for therapeutic intervention

Background: Patients (pts) treated for early stage breast cancer (BC) have a 30% lifetime risk of developing incurable, distant metastatic disease. Yet, standard monitoring after definitive therapy for primary disease is passive observation. Numerous studies have demonstrated that dormant bone marrow (BM) disseminated tumor cells (DTCs) are independently associated with recurrence, but assessment of DTCs is not performed in clinical practice, largely because of concerns about the acceptability and logistics of bone marrow aspiration (BMA) and lack of established therapies that target DTCs. As part of a large scale screening study for a clinical trial targeting DTCs, we examined pt attitudes about DTC screening and subsequently assessed feasibility and tolerability of BM DTC assessment. Methods: The PENN-SURMOUNT (Surveillance Markers of Utility for Recurrence after (Neo)adjuvant Therapy) Screening Study is a single center prospective, longitudinal cohort study examining BM and blood biomarkers of minimal residual disease (MRD) among pts within 5 years of BC diagnosis, who meet one of the following high risk criteria: positive axillary nodes, triple negative biology, ER+ with Oncotype Dx ≥ 25 and/or high risk Mammaprint, or residual disease (RD) after neoadjuvant chemotherapy (NACT). Consented pts undergo a baseline outpatient BMA; if negative, pts can repeat screening annually. During trial design, we surveyed 25 women with stage 2-3 BC at random from the breast clinic at the University of Pennsylvania to assess feasibility. On the SURMOUNT Study, we collected demographic and clinical characteristics of pts, and patient-centered survey data regarding feasibility and acceptability of the BMA that is administered within 48 hours of the procedure. Results: In the pre-trial feasibility survey, 21/25 (84%) pts indicated they were very/definitely interested in knowing if they harbored DTCs. Of those, 18 (86%) indicated moderate/definite interest in testing for DTCs with BMA after the BMA was described to them in detail. 20 (95%) of pts indicated moderate/definite interest in taking oral therapy to eradicate DTCs. 14 (67%) pts stated undergoing up to 3 additional BMA would not change their likelihood of undergoing the clinical trial; only 1 stated much less likely. In the subsequent SURMOUNT study, 361 pts have been referred to date; 167 were eligible, and 136 (81%) subsequently enrolled. 21 (13%) are still in screening. 130 pts have had at least 1 BMA with annual re-screens in 37 (year 1) and 8 (year 2). 39% traveled >50 miles to participate. Post-BMA symptoms were rare (bleeding 2%; redness 12%) though 59%/70% reported mild-moderate pain/tenderness. After BMA, 47%/29%/25% reported it was better/same/worse than expected. 30%/32%/22% reported minimal/moderate/high anxiety prior to the BMA. Afterward, only 20%/5%/4% reported minimal/moderate/high residual anxiety. In 128 pts with results, 38 (30%) have ≥ 1 DTC (30 initial, 8 on follow-up); by risk group: 20/77 (26%) node positive, 20/64 (31%) triple negative, 3/8 (38%) ER+/RS≥25, 7/29 (24%) with RD post-NACT. DTC+ pts were similar to DTC- in median age (50.4), race, distance traveled, menopausal status and BMI. 94% of DTC+ pts have entered the CLEVER clinical trial. Conclusion: A majority of BC survivors want to know DTC status; a majority of these are willing to have BMA and enroll on a clinical therapeutic trial, many are willing to travel to participate and are willing to undergo annual BMA assessment. The SURMOUNT study shows that screening for DTCs is feasible and effective in identifying pts for therapeutic intervention targeting MRD to reduce recurrence. Citation Format: Isoris Nivar, Tara Kauffman, Lauren Bayne, Paul Wiley, Brooke Goodspeed, Michael Feldman, Lewis Chodosh, Amy Clark, Angela DeMichele. Patient attitudes, experience and results of screening for minimal residual disease (MRD) for therapeutic intervention [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-12-01.