Effectiveness of the online Acceptance and Commitment Therapy intervention "Embrace Pain" for cancer survivors with chronic painful chemotherapy-induced peripheral neuropathy: study protocol for a randomized controlled trial

Background: About 30% of cancer survivors suffer from chemotherapy-induced peripheral neuropathy (CIPN) >= 6 months after completion of chemotherapy. This condition, for which treatment options are scarce, comes with limitations in daily life functioning and decreased quality of life. The current study examines the effectiveness of an online self-help intervention based on Acceptance and Commitment Therapy (ACT) in comparison to a waiting list condition (WLC) to deal with CIPN. In addition, it examines which factors moderate effects and to what extent the effects differ between guided and unguided ACT intervention. Methods: A two-parallel, non-blinded randomized controlled trial (RCT) will be carried out. Adult cancer survivors who experience painful CIPN for at least 3 months and completed chemotherapy at least 6 months ago will be recruited (n=146). In the intervention condition, participants will follow an 8-week self-management course containing 6 modules regarding psychoeducation and ACT processes, including therapeutic email guidance. By means of text and experiential exercises, supplemented with illustrations, metaphors, and audio files, people will learn to carry out value-oriented activities in their daily life with pain. Participants will learn new ways of coping with pain, including reducing pain avoidance and increasing pain acceptance. Participants in the WLC will be invited to follow the intervention without therapeutic guidance 5 months after start. Pain interference is the primary outcome, while psychological distress, quality of life, CIPN symptom severity, pain intensity, psychological flexibility, mindfulness skills, values-based living, and pain catastrophizing will serve as secondary outcomes. All outcome measures will be evaluated at inclusion and baseline, early-intervention, mid-intervention, post-treatment, and 3- and 6-month post-treatment. Qualitative interviews will be conducted post-treatment regarding experiences, usage, usability, content fit, and satisfaction with the intervention. Discussion: This study will provide valuable information on the effectiveness of an online self-help intervention based on ACT versus WLC for chronic painful CIPN patients.