Colorectal adenocarcinoma confirmed
Adults with biopsy-proven colon or rectal adenocarcinoma. Covers staging and MDT referral.
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Colorectal SurgeryDiagnostic
Colorectal Cancer Staging Workup
Colorectal Cancer Staging Workup: Colorectal adenocarcinoma confirmed → Obstruction, perforation or major bleeding: acute surgical care first → Baseline...
Pathway Overview
15 steps
Algorithm Steps
15 total
01Start 02Warning Obstruction, perforation or major bleeding: acute surgical care first
Stabilise and get urgent surgical review. If stable, CT chest, abdomen and pelvis before surgery. Complete staging and MDT review after the acute episode.
- Right-sided obstruction: emergency right hemicolectomy
- Left-sided obstruction: stent or emergency surgery (curative); consider stent (palliative)
- Perforation or peritonitis: emergency surgery
03Action Baseline workup
History, family cancer history, examination and ECOG status. Bloods: FBC, UEC, LFTs, CEA.
- Complete colonoscopy; if blocked, CT colonography, then colonoscopy of any remaining colon 3 to 6 months after surgery
- Rectal: DRE and rigid sigmoidoscopy for tumour height
- Pathology review: grade, LVI; synoptic report
04Action MMR/MSI testing: all patients
IHC or MSI on the biopsy, at the same time as staging. The result guides treatment and Lynch syndrome referral.
- MLH1 loss: test BRAF V600E or MLH1 methylation; both negative: refer to familial cancer service
- Other dMMR, age under 50 or strong family history: refer to familial cancer service
- Germline testing needs pre-test counselling and consent
05Warning Pregnancy, contrast allergy or low eGFR: change the imaging plan
Discuss with radiology before the staging scans.
- Pregnancy: MRI without gadolinium; CT only if essential; involve obstetrics
- IV CT contrast not possible: MRI abdomen/pelvis plus non-contrast CT chest
- Low eGFR or past contrast reaction: follow local contrast policy
06Action Staging imaging: CT chest, abdomen and pelvis with IV contrast
All patients.
- Rectal: MRI pelvis (rectal protocol) for T, N, MRF, EMVI and tumour height
- Rectal cT1 or early cT2, local excision possible: add endorectal ultrasound
- Indeterminate liver lesion or liver-only metastases: MRI liver
- PET-CT: suspected or potentially resectable metastases; not routine
07Warning Before any chemotherapy or pelvic RT: DPYD test and fertility referral
Order early, so results are ready before the MDT plan starts.
- DPYD variant (DPD deficiency): 5-FU or capecitabine can be fatal; reduce the dose or use another drug
- Reproductive age: discuss fertility; refer for preservation before treatment
08Decision Distant metastases on staging?
- If Yes
09Action Metastatic: MDT with liver, lung or peritoneal surgeon
Before systemic therapy, test RAS (KRAS, NRAS), BRAF V600E, HER2 and MMR/MSI.
- Liver-only metastases: MRI liver; PET-CT if potentially resectable
- Assess resectability of liver, lung and peritoneal disease
- Symptomatic primary (obstruction, bleeding): manage first
10End Metastatic: treat per MDT plan
Systemic therapy chosen by biomarkers; resection or ablation of metastases if suitable.
If No11Decision No metastases: is the tumour in the rectum?
Rectal: lower edge below the sigmoid take-off on MRI or CT. Rectosigmoid or unsure: MDT radiology review.
- If Yes
- Rectum
12Action Rectal, no metastases: MDT before any treatment
MDT within 2 weeks of diagnosis and staging. dMMR/MSI-H: checkpoint inhibitor therapy first (trial or access program).
- cT3-4, node-positive or MRF threatened: neoadjuvant therapy before surgery
- cT1-2 N0: surgery (TME, or local excision for selected cT1); no preoperative RT
- Complete response after neoadjuvant therapy: watch-and-wait only in an experienced centre
13End Rectal cancer: treat per MDT plan
Neoadjuvant therapy, surgery or organ preservation, as the MDT decided.
If No- Colon
14Action Colon, no metastases: MDT, then resection
MDT within 2 weeks of diagnosis and staging. Most patients have resection first.
- dMMR/MSI-H, locally advanced: MDT for neoadjuvant immunotherapy (trial or access program); chemotherapy gives little benefit
- pMMR cT4: consider preoperative chemotherapy
- Adjuvant therapy depends on the pathological stage
15End Colon cancer: resection per MDT plan
Oncological resection with en bloc lymphadenectomy; examine at least 12 lymph nodes.
Guideline Source
NCCN Clinical Practice Guidelines in Oncology: Colon Cancer and Rectal Cancer (Version 2.2026)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Staging and MDT referral only; the MDT decides treatment.
- Clinical stage can change after surgery; adjuvant therapy uses the pathological stage.
- Neoadjuvant immunotherapy for dMMR disease is usually given in a trial or access program.
Contraindicated Populations
Children and adolescents under 18 yearsNon-adenocarcinoma histology (neuroendocrine tumour, lymphoma, GIST, anal squamous cell carcinoma)
Applicable Regions
USAUUKEU
AU: Optimal care pathway for people with colorectal cancer (2nd edn, updated June 2026): MDT within 2 weeks of diagnosis and staging; universal MMR testing.
UK: NICE NG151 Colorectal cancer.
US: NCCN Colon Cancer and Rectal Cancer guidelines.
Version 2Next review: 2027-09-30
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Frequently Asked Questions
What is the Colorectal Cancer Staging Workup?
The Colorectal Cancer Staging Workup is a diagnostic clinical algorithm for Colorectal Surgery. It provides a structured decision tree to guide clinical decision-making, based on NCCN Clinical Practice Guidelines in Oncology: Colon Cancer and Rectal Cancer (Version 2.2026).
What guideline is the Colorectal Cancer Staging Workup based on?
This algorithm is based on NCCN Clinical Practice Guidelines in Oncology: Colon Cancer and Rectal Cancer (Version 2.2026).
What are the limitations of the Colorectal Cancer Staging Workup?
Known limitations include: Staging and MDT referral only; the MDT decides treatment.; Clinical stage can change after surgery; adjuvant therapy uses the pathological stage.; Neoadjuvant immunotherapy for dMMR disease is usually given in a trial or access program.. Individual patient factors may require deviation from these recommendations.
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