Colorectal tumours ✅

Related Subjects: |Colorectal cancer |Colorectal polyps |Ulcerative Colitis |Acute Severe Colitis |Crohn's disease |Coeliac disease

🧪 Suspected colorectal cancer cannot be excluded without definitive investigation. Options include barium enema + rigid sigmoidoscopy, CT pneumocolon, or colonoscopy. CEA (Carcinoembryonic Antigen) is useful for monitoring recurrence but not for diagnosis. 🚨 NICE NG12 Referral: Urgent 2-week wait referral if adult ≥40 with unexplained weight loss + abdominal pain, ≥50 with rectal bleeding, or iron-deficiency anaemia.

📖 About

• 💡 A leading cause of cancer in older adults, arising from accumulation of genetic mutations in colonic epithelium.
• ➡️ Most colorectal cancers (CRC) evolve from adenomatous polyps (adenoma–carcinoma sequence).
• Exceptions: HNPCC (Lynch syndrome) and colitis-associated CRC.

⚠️ Risk Factors

• 👨 Male sex
• 🍖 Diet: low fibre, high fat/red meat intake
• ⬆️ Sporadic cases (~70%)
• IBD: Ulcerative colitis >10 years, Crohn’s colitis (long duration)
• Hx cholecystectomy (↑ bile salts)
• Family history / genetic syndromes: HNPCC, FAP

🧬 Aetiology & Genetic Mechanisms

• 🍔 Dietary: low fibre, high fat
• 🧪 Oncogenes: K-ras, c-myc activation
• 🛑 Tumour suppressors lost: APC, p53, DCC
• Mismatch repair defects: hMSH2, hMLH1 → Lynch syndrome
• Classical sequence: Normal mucosa → Dysplasia → Adenoma → Adenocarcinoma
• Right-sided tumours are typical in familial syndromes (FAP, HNPCC)

🔎 Pathology Types

• 🩸 Ulcerating → bleeding, anaemia
• 🌱 Polypoid type
• 🌀 Annular (“apple-core”) → obstruction
• Diffuse / infiltrating / colloid (mucus-secreting)

🌱 Polyps & Malignancy Risk

• Histology: Villous > Tubulovillous > Tubular
• Size: Larger = ↑ risk
• Dysplasia: Higher grade = ↑ malignancy risk

📊 Histological Grades

• Grade I – Well differentiated
• Grade II/III – Moderately differentiated
• Grade IV – Anaplastic

📍 Tumour Location

• Rectum + Sigmoid: ~60%
• Ascending colon: ~20%
• Transverse/descending colon: ~20%

📡 Spread

• Direct invasion up to 2 cm from margin
• 🩸 Haematogenous: Liver (commonest), lungs, adrenals, kidneys, bones
• 🌿 Lymphatic: Para-aortic, supraclavicular
• Krukenberg metastases → ovaries
• May seed surgical wounds/ports

🧾 Clinical Presentation

• Rectal: PR bleeding, tenesmus, altered bowel habit, palpable mass
• Left colon: Constipation, altered habits, blood, iron deficiency anaemia, sigmoid mass
• Right colon: Occult bleeding → anaemia, weight loss, late obstruction
• 🚨 Acute: Obstruction, perforation, peritonitis, massive bleed, fistula (e.g., colovesical)

🧪 Investigations

• Bloods: FBC (anaemia), ferritin, folate, B12, LFTs (ALP for liver mets)
• Imaging: USS, CT, MRI, CXR for staging; Endorectal US for rectal cancer
• Endoscopy: Colonoscopy + biopsy = gold standard. Alternatives: barium enema, CT pneumocolon
• Marker: CEA – not diagnostic but valuable for monitoring recurrence

📑 Duke’s (Modified) Staging

🛡 Prevention

• Colectomy in FAP → markedly increases survival
• Aspirin/NSAIDs may be protective in some patients
• Lifestyle: High fibre diet, physical activity, weight management, alcohol moderation

🔧 Definitive Management

• Surgical resections vary by site: Right/Left hemicolectomy, sigmoid colectomy, anterior resection (rectal), abdominoperineal resection (low rectal → colostomy)
• Solitary liver mets may be resectable → potential cure

💊 Chemotherapy

• 5-Fluorouracil + Leucovorin mainstay (esp. Dukes C, some Dukes B); Capecitabine as alternative
• Other agents: Oxaliplatin, Irinotecan, Cetuximab (EGFR inhibitor), Bevacizumab (VEGF inhibitor)

🤲 Palliative Care

• Palliative surgery for obstruction, fistulas, bleeding (e.g., colostomy)
• Radiotherapy mainly for rectal tumours (pain/bleeding control, pre/post-op to ↓ recurrence)

📌 Post-Resection Surveillance (NICE NG151)

• Colonoscopy at 1 year, then 3 years, then 5 years (adjust for polyps/stage)
• CEA every 3–6 months for 5 years to detect recurrence
• Clinical review and imaging as indicated for stage II–III

Cases - Colorectal Tumours

• Case 1 (Right-sided colon cancer): 72F with fatigue, pallor, iron-deficiency anaemia; caecal mass on colonoscopy. Management: Right hemicolectomy, iron supplementation. Outcome: Uneventful recovery, enters 5-year surveillance programme.
• Case 2 (Left-sided colon cancer): 64M, altered bowel habit, rectal bleeding; sigmoid lesion on colonoscopy. Management: Left hemicolectomy; no adjuvant chemo required. Outcome: Disease-free at 2-year follow-up.
• Case 3 (Rectal cancer with local spread): 58F, rectal bleeding, mucus, stool calibre change; T3N+ on MRI. Management: Neoadjuvant chemoradiotherapy → low anterior resection with protective ileostomy → adjuvant chemo. Outcome: Ileostomy reversed at 6 months, no recurrence at 18 months.

Teaching Commentary 🧑‍⚕️

Colorectal tumours vary by site: • Right-sided → occult bleeding, anaemia, bulky. • Left-sided → change in bowel habit, obstruction, bleeding. • Rectal → tenesmus, mucus, altered stool calibre. Diagnosis is via colonoscopy with biopsy and staging (CT/MRI). Management is surgical resection ± adjuvant chemo/radiotherapy depending on site and stage. Screening (faecal immunochemical test, colonoscopy) is key for early detection. Surveillance post-resection is essential to detect recurrence early. Lifestyle advice, aspirin use, and management of polyps improve long-term outcomes.