Any patient with a suspected primary adenocarcinoma of the colon, sigmoid or rectum undergoing surgery are eligible. The date of surgery must be known prior to registration. This trial aims to determine if image mapping techniques can improve the concordance between imaging and pathology detection of tumour deposits. Lymph nodes and tumour deposits will be identified on pre-operative scans and mapped by radiologists then shared with pathologists prior to processing the resected specimen. Patients will be managed at their local hospital with standard follow-up. Patients will be followed up for 5 years.

A prospective interventional multi-centre study, COMET aims to prove the accuracy of imaging diagnosis of extranodal tumour deposits (TD) and their adverse effect on prognosis of colorectal cancers. The proposed intervention will be additional radiological and pathological assessment and the reporting of supplementary diagnostic information which would not otherwise have been available. This may affect treatment according to local MDT protocols and also affect the provision of prognostic information to patients in subsequent discussions.

Inclusion Criteria:

1. Suspected primary adenocarcinoma of the colon, sigmoid or rectum (proven by biopsy taken as part of routine clinical practice, patients to be withdrawn if not subsequently adenocarcinoma on pathology).
2. Amenable to surgical resection.
3. Disease spread assessed on imaging
4. Patients having primary surgery and those undergoing neoadjuvant treatment will be included.
5. All must have had baseline staging scans and those undergoing neoadjuvant therapy must also have had a post-treatment scan.
6. Patients aged 16 years and over

Exclusion Criteria:

1. Patients with recurrent tumours
2. Synchronous tumours
3. Under the age of 16 years
4. Unable to give informed consent.