Exercise That Feels as Good as Possible: Acceptability of an Affect‐Based Exercise Prescription Among Stage 0–III Breast Cancer Survivors

Background Leaders in the field have called for exercise counseling to become standard of care by 2029. An Affect‐based exercise prescription (Affect‐Rx) may be a viable strategy for supporting this effort. Aims Guided by the ORBIT Model for developing behavioral treatments, this Phase 1b study evaluated breast cancer survivors' perceived acceptability of Affect‐Rx. Additionally, the feasibility of trial methods and opportunities for protocol refinements were assessed. Method Participants were 36 stage 0–III breast cancer survivors within 5 years of completing primary cancer treatment. Demographics were collected at baseline and via medical record review. Affect‐Rx was delivered in conjunction with a low‐touch, physical activity promotion intervention over videoconference call. At end‐of‐study, participants rated Affect‐Rx using the Treatment Acceptability and Preferences (TAP) Measure. Participants responded to the Stanford L‐Cat at baseline and end‐of‐study. ActiGraph wGT3X‐BT accelerometers measured moderate‐vigorous physical activity (MVPA) over 10‐day periods at baseline and follow‐up. Results Affect‐Rx was rated acceptable (TAP overall M = 3.30, SD = 0.53). Study retention and accelerometer measurement completion was ≥ 80% across time. L‐Cat scores were discordant from accelerometer‐measured MVPA at baseline. Conclusions Affect‐Rx warrants further testing. The trial methods were feasible; however, physical inactivity verification procedures along with targeted recruitment efforts are needed to support future work. The field needs intervention strategies that can be deployed with limited resources and at low cost to offer survivors exercise counseling support in line with the new National Standards for Cancer Survivorship Care, the affect‐based exercise prescription is designed to serve this mission. Trial Registration The study protocol was registered with ClinicalTrials.gov prior to the initiation of participant recruitment NCT04903249