Inclusion Criteria:  diagnosis of a solid malignancy cancer, (i) non-metastatic disease or (ii) metastatic disease; between 3 and 7 months after start of treatment with adjuvant or 1st line chemotherapy or with adjuvant or 1st line immunotherapy; life expectancy of more than 3 months.  Exclusion Criteria:  age < 18; insufficient command of the Dutch language; severe psychopathology, other than mood or anxiety disorder (e.g. lifetime history of bipolar disorder, schizophrenia, MDD with psychotic features, schizoaffective disorders); severe cognitive impairments (e.g. dementia); patients with a (indication of) brain tumor or -metastases; a history of severe drug or alcohol abuse within past 6 months; not competent in the use of a mobile phone no informed consent.