Effectiveness of structured psycho-oncological counseling for relatives of lung cancer patients based on the CALM approach-study protocol of a randomized controlled trial.

Background: The high incidence combined with the high lethality and bad prognosis of lung cancer highlight the need for psycho-oncological care for both patients and their relatives. While psychological interventions for relatives might be helpful, further research on the impact of specific interventions is necessary. Therefore, this trial aims to evaluate structured psycho-oncological counseling for relatives of lung cancer patients based on the Managing Cancer And Living Meaningfully (CALM) approach compared to usual care. In addition, we explore the impact of psycho-oncological support of relatives on the patients' mental health outcomes.

Methods: The study is a single-center, prospective, randomized controlled trial with two measurement time points. Relatives of lung cancer patients and, thus, the patients themselves (i.e., dyads) are randomly allocated to the intervention group (IG) or the control group (CG) regardless of their disease or treatment stage. Relatives in the IG receive structured counseling based on the CALM approach (three to six sessions with psycho-oncologists). The CG receives usual psycho-oncological care. In addition, cancer patients in both study arms can request psycho-oncological support (usual care) as needed, but they will not get a specific intervention. Relatives and patients complete assessments at baseline (T0) and after the intervention/6 weeks (T1). The primary outcome for relatives is anxiety. Relatives' secondary outcomes include depressive symptoms, distress, supportive care needs, and quality of life. Patients' outcomes include anxiety, depression, and distress. All outcomes are assessed using self-report validated questionnaires. Intervention effects will be evaluated using analysis of covariance (ANCOVA) adjusting for baseline values. Power calculations reveal the need to enroll 200 subjects to detect an effect of d = 0.4.

Discussion: The study will provide evidence for the effectiveness of the CALM intervention in relatives of lung cancer patients. Furthermore, study results will contribute to a better understanding of the effectiveness of a psycho-oncological intervention for highly impaired cancer patients and their relatives. If the CALM intervention positively affects the relatives' psychosocial outcome, it may be implemented in routine care.

Trial Registration: German Clinical Trials Register DRKS00030077. Retrospectively registered on 26 October 2022.