ObjectivePatients and partners both cope individually and as a dyad with challenges related to a breast cancer diagnosis. The objective of this study was to evaluate the effect of a psychological attachment‐oriented couple intervention for breast cancer patients and partners in the early treatment phase.MethodsA randomised controlled trial including 198 recently diagnosed breast cancer patients and their partners. Couples were randomised to the Hand in Hand (HiH) intervention in addition to usual care or to usual care only. Self‐report assessments were conducted for both patients and partners at baseline, postintervention (5 months), and follow‐up (10 months), assessing cancer‐related distress, symptoms of anxiety and depression, and dyadic adjustment. Patients' cancer‐related distress was the primary outcome.ResultsCancer‐related distress decreased over time in both patients and partners, but the intervention did not significantly affect this decrease at postintervention (P = .08) or follow‐up (P = .71). A significant positive effect was found on dyadic adjustment at follow‐up for both patients (P = .04) and partners (P = .02).ConclusionsThere was no significant effect of the HiH intervention cancer‐related distress. The results suggest that most couples can cope with cancer‐related distress in the context of usual care. However, the positive effect on dyadic adjustment implies that the HiH intervention benefitted both patients and partners. Future studies should investigate how to integrate a couple focus in usual cancer care to improve dyadic coping in the early treatment phase.

Socioeconomic characteristics of patients and partners, and morbidity of partners may influence participation in couple-based psychosocial breast cancer research. Breast cancer-related characteristics do not seem to influence participation.