Testing for clonal hematopoiesis of indeterminate potential in breast cancer survivors.

e24108 Background: Clonal hematopoiesis of Indeterminate Potential (CHIP) is associated with adverse clinical outcomes including increased risk of hematologic malignancies and heart disease. Limited data suggest an increased prevalence of CHIP in patients treated for solid tumors, particularly after exposure to radiation and chemotherapy. CHIP testing may inform risk-reduction strategies for cancer survivors. Little is known about patient knowledge, attitudes, and preferences regarding CHIP testing. Methods: We surveyed survivors without history of recurrence participating in an ongoing prospective cohort study of young women with breast cancer (BC). The survey was sent by email and included an introduction to CHIP including risk factors and clinical associations. Respondents then reviewed a vignette and were asked about CHIP testing preferences (definitely/probably test vs. definitely/probably not test) considering sequentially: 1) population-based 10-year risk of BC recurrence, hematological malignancy and heart disease; 2) estimated increase in these risks with CHIP; 3) current CHIP management; 4) a dedicated CHIP clinic; and 5) a theoretical CHIP treatment. Changes in preferences from the prior scenario were evaluated with the McNemar's test using a type I error rate of 5%. Results: 528/642 (82.2%) eligible women responded to the survey, at a median age of 46 (range: 31-54) years (median time from diagnosis: 108 months (range: 60-168)), and 88% were white. Most had stage 1/2 BC (78.8%) and had received chemotherapy (73.1%) and/or radiation (61.9%). 93.6% had never heard of CHIP prior to survey. After initial patient vignette presentation, most women (87.1%,) recommended CHIP testing if offered. Preferences for testing decreased (p<0.05) when considering population-based risks, with 11.1% shifting their preference from CHIP testing to not testing. After considering increased risks associated with CHIP, interest in testing increased (p<0.05), with 10.1% shifting their preference to testing. Interest significantly (p<0.05) increased with the possibility of managing CHIP through a clinic or a hypothetical CHIP treatment, with 7.2% and 14.1% switching their preferences towards testing, respectively. Finally, 75.8% responded that they themselves, after learning about CHIP and reviewing the vignette, would want to have CHIP testing; 28.2% reported that learning about CHIP and the associated risks caused them at least moderate anxiety. Conclusion: Few young BC survivors were aware of CHIP yet most indicated an interest in testing after learning about it. Testing preferences were influenced by risks presented and potential management strategies. Findings highlight the importance of effective risk communication and the need for adequate psychosocial support when considering testing for CHIP and other potential clinical biomarkers predictive of cancer and other medical risks in cancer survivors.