Oncovox: A randomised controlled trial of a web-based acceptance and commitment therapy for breast cancer patients

iACT interventions can be cost-effective and convenient for providing evidence-based care to breast cancer patients (BCPs). Determining the feasibility, acceptability, and efficacy of Oncovox, a guided iACT intervention designed to improve psychosocial outcomes in BCP undergoing treatment. A parallel, two-arm, open-label, randomized controlled trial (RCT) evaluating an 8-module intervention. Participants were randomized to the iACT group (N = 75) or a waitlist group (N = 75). Primary outcomes: Quality of Life (QoL), Behavioral Activation (BA), Symptom Interference (SI) and Reward Noticing (RN). Secondary outcomes: anxiety and depression symptoms and psychological flexibility (PF). Measurements were made pre- and post-intervention, twice during the intervention, and at 1- and 2-month follow-up. SI, anxiety and depression, and PF improved significantly, with further improvement at follow-up. QoL, BA and RN improved moderately, but only when imputed data were analyzed. Oncovox has good dissemination potential and could be appropriately implemented in stepped care. •ACT is adaptable for online delivery for breast cancer patients.•Oncovox as iACT for BCPs is feasible, useful and renders good user satisfaction.•Oncovox improves symptom interference, anxiety, and depression symptoms.•Oncovox improves psychological flexibility.•Oncovox is more effective for patients with a more invasive type of surgery.