The intervention is shared decision-making. The implementation strategy to foster shared decision-making in routine cancer care is a multicomponent implementation program. The implementation program consists of the following components:

1. shared decision-making trainings for health care professionals,
2. individual coaching for physicians,
3. patient activation strategy,
4. provision of patient information material and decision aids,
5. revision of the clinics quality management documents, and
6. critical reflection of current organization of multidisciplinary team meetings.

Implementation: after baseline assessment (t0) for clinic 1, after assessment at t1 for clinic 2, after assessment at t2 for clinic 3.

Action to employ shared decision-making as measured by the German version of the 9-item Shared Decision Making Questionnaire (SDM-Q-9)

Action to employ shared decision-making as measured by the German version of the Observer OPTION 5 scale using audio-recorded medical encounters. The Observer OPTION 5 scale measures the extent to which clinicians involve patients in decision-making. Each of the 5 items is assessed on a scale ranging from 0 to 4 with higher values indicating more involvement of patients in decision-making. A sum score is calculated (ranging from 0 to 20) and rescaled to be between 0 to 100, for ease of interpretation.