Impacts of toxicity on patient treatment choices for metastatic breast cancer.

18 Background: Most patients with metastatic breast cancer (MBC) are treated with chemotherapy and/or targeted therapy with varying toxicity profiles. Experience with adverse events (AE) may vary and factor into subsequent treatment decisions. As newer agents and combinations become available, it becomes increasingly important to understand which AEs impact treatment decisions. Methods: The objective was to assess patient experience with AEs and preferences for future treatments. Following focus groups and pretests, an online survey was released by breast cancer organizations to recruit patients with MBC. The survey assessed the impact of experiences on future treatment choices and measured preferences via conjoint analysis (CA). Results: A total of 551 respondents completed the online survey. Among the AEs studied to assess their impact on either treatment stops or breaks, neutropenia topped the list, particularly for a required break. Fatigue, hand and foot syndrome, diarrhea, joint pain and peripheral neuropathy (PN) were high for chosen stops. Five AEs (fatigue, alopecia, diarrhea, PN, neutropenia) were studied extensively. Almost all respondents report experiencing fatigue, ~80% experienced alopecia, and ~66% each of the other 3 AEs. For each AE, the majority of respondents reported their prior experience would not impact a future decision involving the same AE; about 1/3 report they’d be more likely to take a treatment with the same AE; 8% to 18% would be less likely to take a treatment with the same AE. CA was also used to assess influence of the 5 AEs on future decisions. Within the tested ranges of likelihood, severity and duration, alopecia had the highest impact; PN, diarrhea, and neutropenia were in the middle; and fatigue was lowest. Further analysis is ongoing and final results will include differences in patient subgroups. Conclusions: This information informs priorities for development of new therapies allowing additional attention on AEs that matter most to patients. In addition, these results may generate discussion and consideration of patient preferences in conversations about care and treatment selection.