Chronic cancer-related fatigue (CCRF) is a disturbing condition that persists in up to 25% of cancer patients after completion of treatment. While mindfulness-based interventions are effective in relieving CCRF, these typically target the patient alone. Growing evidence suggests that including partners and targeting the dyadic context can increase and broaden the interventions' efficacy. The proposed study is a pilot trial testing the acceptability and potential efficacy of a mindfulness intervention directed at couples.

This is a 1-arm pilot trial. Recruitment will take place via a hospital, the Helen Dowling Institute and self-referral. The target is to include 34 couples (i.e. 68 participants). All participating cancer patients and their partners will be allocated to the couple mindfulness-based cognitive behavioral therapy, provided via internet (couple eMBCT), called 'COMPANION' (in Dutch: 'Samen Minder Moe') Assessments include three questionnaires (i.e. before starting the intervention (T0), after completing the intervention (T1), and 1 month after T1 (T2)). The assessments include also weekly diaries during a period of 17-22 weeks. A subsample of patients (n ≈ 5) and partners (n ≈ 5) as well as the therapists providing the couple eMBCT will participate in final focus groups. The primary objectives of COMPANION study 2 are to determine the acceptability of the couple intervention and the potential efficacy for patient fatigue. Secondary objectives are to examine the feasibility of trial procedures and the potential working mechanisms of the couple intervention.

Inclusion Criteria:

Only couples are eligible for participation. In order to be eligible, the couple must meet each of the following criteria:

1. The patient has received a cancer diagnosis (all malignancies will be included);
2. The patient completed cancer treatment with either curative or palliative intent ≥ 3 months earlier. Patients who currently receive hormone therapy are eligible;
3. The patient experiences severe levels of fatigue (score of ≥ 35 on the Checklist Individual Strength, subscale fatigue severity (CIS-fatigue));
4. The patient has been suffering from severe fatigue for ≥ 3 months (as self-reported by the patient);
5. The patient was ≥ 18 years old at disease onset;
6. The partner is ≥ 18 years old;
7. Both couple members live together;
8. Both couple members have good command of the Dutch language (checked implicitly during registration);
9. Both couple members have adequate computer literacy and have access to an internet-connected computer, laptop or tablet (based on self-report);
10. Both couple members agree to participate in the research.

Exclusion Criteria:

The couple will be excluded in case:

1. The patient is currently following an evidence-based therapy for CCRF (i.e. Cognitive-Behavioral Therapy, mindfulness-based therapy, exercising/physiotherapy) as self-reported at the (telephone) screening;

2. The patient suffers from a condition that can explain his/her fatigue and is potentially treatable (e.g. anemia);

3. The therapist decides, based on information collected during the intake session, that the intervention is not suitable for the couple. Criteria that will be considered include, but are not limited to:

   • presence of severe psychiatric morbidity such as suicidal ideation and/or psychosis (as assessed by the therapist at the intake session). Mild depression is not an exclusion criterion. A score of ≥ 20 on the Hospital Anxiety and Depression Scale (HADS) at T0 is considered indicative of depression. Therefore, if the patient or the partner scores ≥ 20, the therapist will determine at the intake whether the participant has suicidal ideation or suffers from other severe psychiatric morbidity. A participant (and thus the couple) will be excluded if, according to the therapist, that is the case;
   • presence of substance abuse, except for smoking.

Collected quantitative IPD (questionnaires, diaries) can potentially be shared.

After study completion and publication of outcome data.

The anonymized data that support the findings of this study will become available from the principle investigators upon reasonable request, including a data analysis plan and research questions. Permission for data sharing will be asked from the medical ethical commission.