High-yield map
Key points before the detail
- 01
Right-sided cancer often presents with iron-deficiency anaemia; left-sided cancer more often obstructs.
- 02
Symptomatic FIT ≥10 µg Hb/g meets the NICE referral threshold, but negative FIT still needs safety-netting.
- 03
Diagnose with colonoscopy/biopsy and stage with CT chest-abdomen-pelvis.
- 04
Rectal cancer needs high-resolution pelvic MRI.
- 05
All new colorectal cancers need MMR/MSI assessment.
1. Presentation by site
| Site | Common presentation |
|---|---|
| Right colon | Iron-deficiency anaemia, fatigue, weight loss, occult bleeding or a mass. |
| Left colon | Change in bowel habit, colicky pain, visible bleeding and obstruction. |
| Rectum | Rectal bleeding, urgency, tenesmus, mucus and incomplete evacuation. |
| Advanced disease | Liver/lung metastases, ascites, obstruction or perforation. |
2. Symptomatic FIT
- Use quantitative FIT in the NICE symptomatic pathway when appropriate.
- A result ≥10 micrograms haemoglobin per gram faeces meets the suspected colorectal cancer referral threshold.
- Safety-net patients who do not return a sample or whose result is below threshold but symptoms persist.
- FIT must not delay emergency assessment of obstruction, perforation or major bleeding.
3. Diagnosis and staging
| Question | Investigation |
|---|---|
| Is there a lesion? | Colonoscopy with biopsy; CT colonography if colonoscopy is incomplete or unsuitable. |
| Has disease spread? | Contrast CT chest, abdomen and pelvis; baseline CEA supports follow-up but is not diagnostic. |
| How advanced is rectal cancer locally? | High-resolution pelvic MRI for T stage, nodes, EMVI and mesorectal fascia/CRM. |
| Could this be hereditary or immunotherapy-responsive? | MMR protein or MSI testing in every new colorectal cancer. |
| Metastatic biomarker planning | RAS, BRAF and other profiling according to oncology/MDT pathways. |
4. Colon cancer surgery
- Resection follows vascular and mesocolic anatomy with en-bloc regional lymphatic clearance.
- Right-sided tumours generally require right-sided oncological colectomy; descending/sigmoid tumours use left/sigmoid resections appropriate to vascular territory.
- Do not peel a tumour off an adherent organ when cure is intended; suspected invasion is managed by en-bloc multivisceral resection when feasible.
5. Rectal cancer
- Discuss bowel, urinary and sexual function, low anterior resection syndrome and stoma possibility before treatment.
| Pattern | Management principle |
|---|---|
| Selected low-risk early T1 lesion | Organ-preserving endoscopic/transanal excision in expert units. |
| Operable mid/low rectal cancer | TME-based radical surgery. |
| Threatened margin/locally advanced disease | Neoadjuvant strategy guided by MRI and MDT. |
| Very low tumour | Low anterior, intersphincteric or abdominoperineal strategy according to margins, sphincter involvement, function and preference. |
6. Obstruction and perforation
- Resuscitate first and preserve oncological quality where physiology permits.
- Right-sided obstruction often proceeds to oncological resection if the patient and bowel are suitable.
- Left-sided obstruction may use emergency resection, diversion or selected stenting as a bridge to surgery in experienced services.
- Do not stent through known or suspected free perforation.
7. Pathology, biomarkers and survivorship
- Stage III and selected high-risk stage II disease often receive adjuvant chemotherapy according to pathology and patient factors.
- Potentially resectable liver/lung metastases should be reviewed in specialist MDTs.
- MMR/MSI, RAS and BRAF influence hereditary assessment and systemic therapy.
- Follow-up addresses recurrence surveillance, stoma care, LARS, neuropathy, sexual/urinary function and nutrition.
Active recall
Close the notes and answer these
Try each question from memory before revealing the answer. These public prompts are a small preview of the integrated retrieval system inside SurgAtlas.
01What is the symptomatic FIT referral threshold used in the current SurgAtlas source?
At least 10 micrograms haemoglobin per gram of faeces.
02What staging scan is standard after colorectal cancer diagnosis?
Contrast CT of chest, abdomen and pelvis.
03What additional local staging is required for rectal cancer?
High-resolution pelvic MRI.
04What molecular test should every new colorectal cancer receive?
Mismatch-repair protein or microsatellite-instability testing.
05What operation principle defines mid/low rectal cancer surgery?
Total mesorectal excision (TME) planned from pelvic MRI and margin anatomy.
Sources & editorial basis
References & editorial basis
- SurgAtlas production source. General Surgery — Colorectal Cancer. Public lesson curated from the corresponding production chapter.
- NICE NG151. Colorectal cancer: diagnosis and management; reviewed April 2026.
- NICE NG12. Suspected cancer: recognition and referral, including symptomatic FIT pathways.
This lesson is derived from the corresponding SurgAtlas production teaching material. Where the source makes current management or guideline claims, the public lesson uses the cited contemporary guidance. It is written for education and examination preparation, not as patient-specific clinical advice.
Editorial details
Medical Doctor (MD) · MRCS Part A · Physician · Surgical Educator
SurgAtlas is an educational resource. For patient care, verify current national guidance, local antimicrobial and transfusion policies, specialty pathways and individual patient factors.
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