Patient-led Follow-up from Home After Surgery for Colorectal Carcinoma

inclusion criteria * Age ≥ 21 years * Histologically confirmed colorectal adenocarcinoma without distant metastasis and treated with curative intent surgical resection less than 6 months ago * Scheduled or currently undergoing postoperative surveillance according to national guidelines * Written informed consent by the patient * Access to a smartphone Exclusion criteria * Patients with a severely complicated postoperative course, needing in hospital follow- up longer than 6 months postoperatively * Patients enrolled in other studies that require strict adherence to any specific follow-up practice with regular imaging - yearly or more frequent - of the abdomen and/or thorax * Patients with comorbidity or other malignancy that requires imaging of the abdomen and/or thorax every year or more frequent * Patients with active implantable devices - e.g. pacemaker or implantable defibrillator * Inability to complete the questionnaires due to illiteracy and/or insufficient proficiency of the Dutch language