Inclusion Criteria:  Biopsy proven newly detected adenocarcinoma of the colon or rectum cTany N1-2 Many using TNM 8th edition and based on standard diagnostic imaging including contrast enhanced-CT thorax-abdomen (for colon and rectum) and pelvic MRI (for rectum) Indication for curative local treatment of the primary colon/rectal tumour Signed written informed consent prior to any study specific procedure  For colon cancer patients:  Age > 18 years Indication for surgery including resection of the colon tumour and the corresponding mesentery Surgery can be planned within 3 weeks after diagnostic imaging Surgery takes place in one of the participating centres of this study  For rectal cancer patients:  Age > 50 years* Indication for neoadjuvant (chemo)radiotherapy of the rectal tumour Planned for response assessment after (chemo)radiotherapy with pelvic MRI Planned for surgery or an organ preservation approach in one of the participating centres of this study * Related to the allowed radiation dose per age category for diagnostic imaging and in accordance with the guideline of the Dutch Commission for Radiation Dosimetry (NCS).  Exclusion Criteria:  Inability to provide informed consent Histopathology of mucinous adenocarcinoma WHO > 2 Pregnancy Lactation, unable to substitute for 24 hours after FAPI PET/CT Known second malignant disease that may complicate image interpretation including a second primary at time of colorectal cancer diagnosis Inability to cooperate with the scan process: inability to lie relatively still and in supine for 30-60 minutes or patient body habitus above scanner dimensions Suspicion of peritoneal metastases based on contrast-enhanced CT and/or MRI Treatment setting without local treatment of the primary colorectal tumour  For colon cancer patients:  Absence of diagnostic contrast enhanced-CT thorax-abdomen Refusal of surgery by the patient Indication for neoadjuvant treatment Indication for emergency surgery  For rectal cancer patients:  Contra-indication for MRI Absence of diagnostic pelvic MRI and/or contrast enhanced-CT thorax-abdomen Refusal of neoadjuvant treatment by the patient Absence of response assessment after (chemo)radiotherapy