Background of the study:~The occurrence of cancer constitutes a major stressor, leading to a wide range of emotions. Patients need support from relatives, friends and caregivers to deal with these emotions. Some patients need professional mental health care, in addition to support. Unfortunately, an accurate instrument to identify patients in need of professional mental health care is not available. This leads to important mismatches in the provision of care.~In the field of oncology, the concept of 'distress' is used to refer to emotions associated with cancer. Measurement instruments (e.g. Distress Thermometer) are used to identify patients with clinically relevant distress. This approach results in major inconsistencies.While approximately one in three patients scores above the cut-off for distress, only about one in ten patients accepts mental healthcare, while it is unclear how many need mental health care.~In the field of mental health, it is generally acknowledged that a distinction needs to be made between normal and adaptive emotions versus maladaptive and psychopathological emotions in response to a potentially traumatic event such as cancer. The concept of distress fails to make this distinction. Some patients scoring above the cut-off for distress may indeed experience maladaptive emotions. Other patients scoring above the cut-off may actually experience adaptive emotions, which facilitate coping with cancer. Therefore, in order to provide appropriate care, identification of indicators distinguishing between adaptive and maladaptive emotions in patients with cancer is an urgent research priority.~Objective of the study:~To identify indicators that distinguish between adaptive and maladaptive emotions in patients with cancer, derived from recent innovative developments in the field of mental health.~Study design:~Patients are categorized as having 'adaptive emotions' or 'maladaptive emotions', using a reference standard: (a) a diagnostic mental health interview and questionnaires, or (b) patient's subjective need for professional mental health care. In all patients, emotional symptoms, cancer-treatment related symptoms and activities are assessed during a period of two weeks via mobile phone. Assessments of patients takes place twice; at 3 and 6 months after the start of chemo-or immunotherapy.
Primary Objective: To identify indicators distinguishing between adaptive and maladaptive emotions in patients with cancer.