Smartphone-Based Acceptance and Commitment Therapy for Postmastectomy Pain Syndrome: A Pilot RCT Evaluating Feasibility, Acceptability, and Preliminary Clinical Outcomes.

Objective: This study examined the feasibility and potential acceptability, with exploratory assessment of its effects on pain interference and fear of recurrence, of a smartphone-based acceptance and commitment therapy (ACT) intervention to reduce pain interference and fear of recurrence in breast cancer survivors. Methods: This single-center, parallel-group, randomized controlled pirot trial included breast cancer survivors with postmastectomy pain syndrome who were randomly allocated to an ACT intervention group or control group in a 1:1 ratio. Of the 57 patients screened, 45 were randomly assigned to the ACT group (n = 22) and the control group (n = 23). The ACT app offered an 8-week program with outcome measures for before and after the intervention. Primary outcomes were feasibility and adherence, assessed by intervention completion rate, participants' perceived usefulness, and satisfaction. Secondary outcomes included exploratory clinical measures assessed before and after the intervention. Results: The intervention completion rate for the ACT group was 100%, and the degree to which patients' needs were met and their overall satisfaction was high (>60%). One minor adverse event was reported, but the patient had already recovered by the time of the interview stage, and the event was considered minor. No significant improvements were observed in clinical outcomes. Discussion: The results demonstrate the feasibility and acceptability of smartphone-based ACT interventions. Clinical efficacy was not demonstrated and should be evaluated in future trials with adequately powered samples and participants with higher levels of pain interference.