COMPANION: A Couple Intervention Targeting Cancer-related Fatigue

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.