A protocol for a feasibility study of Cognitive Bias Modification training (IVY) countering fatigue in people with breast cancer

Background: Cancer-related fatigue (CRF) is the most prevalent, distressing, and quality of life disturbing symptom during and after cancer treatment for many cancer types including breast cancer. The experience and burden of this symptom can induce a cognitive bias towards fatigue or a fatigue-related self-image, which can further increase the fatigue symptoms and related behaviour. For this, a Cognitive Bias Modification (CBM) eHealth app (IVY) has been developed. The app aims to counter the fatigue-related self-image and to modify it towards vitality, which might translate to less experienced fatigue and more experienced vitality. This study aims to evaluate the feasibility of the IVY CBM training and the research design of a wait-list control trial. If feasibility is judged sufficient, the effectiveness of the CBM app will also be analyzed on (1) underlying mechanisms (cognitive fatigue bias), (2) symptom fatigue (self-reported fatigue and vitality), and (3) related behaviours (avoidance and all-or-nothing behaviour).

Methods: This feasibility study addresses individuals being treated for breast cancer receiving (neo)adjuvant treatment or metastatic care. The number of target participants is 120 (60 (neo)adjuvant, and 60 metastatic) patients. Both groups will be randomized with 30 people in the IVY treatment group and 30 people in the delayed treatment control group. All participants will receive the training via the IVY app, in which participants categorize words related to vitality with words related to 'I' and words related to fatigue with words related to 'other'. If feasibility is judged sufficient, the effects of the training will be explored on 3 levels: (1) self-identity bias, which will be measured with a short computer task based on the Implicit Association Test (IAT), (2) avoidance and all-or-nothing behaviour, and (3) fatigue and vitality levels, which will all be measured with questionnaires.

Discussion: This study aims to evaluate the feasibility of a larger-scale multi-centre Randomized Controlled Trial (RCT) to investigate a novel eHealth application and, if possible, to give indications on the effectiveness of this intervention to counter fatigue in individuals with breast cancer. Using the IVY CBM app requires very little effort, both in time and cognitive load, which could be especially beneficial for fatigue symptoms.

Trial registration: Registered at the Open Science Framework (OSF; https://osf.io/e85g7/ ) on October 20, 2023.