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Carcinoma of the Stomach

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Incidence & Epidemiology

• Most common primary gastric malignancy: Adenocarcinoma (95%) — Schwartz's, p. 1167
• Other types: Lymphoma, GIST, neuroendocrine tumour, squamous cell carcinoma
• 4th most common cancer worldwide; 2nd leading cause of cancer death globally
• Dramatic decline in incidence in Western countries over the past century (mainly the intestinal type)
• Remains a leading cause of cancer death in Asia and Eastern Europe
• ~28,000 new cases/year in the USA; 5-year survival ~27% (up from 15% in 1975)
• Twice as common in blacks as whites; more common in lower socioeconomic groups
• Disease of the elderly; younger patients tend to have diffuse, aggressive tumours

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Aetiology & Risk Factors

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Premalignant Conditions & Cascade

Normal mucosa → Chronic gastritis (H. pylori) → Atrophic gastritis → Intestinal metaplasia → Dysplasia → Invasive carcinoma

• Intestinal metaplasia — goblet cells histologically identical to small bowel; H. pylori eradication causes regression
• All gastric ulcers should be regarded as malignant until proven otherwise by biopsy

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Pathological Classification

1. Lauren Classification (Most Clinically Important)

Linitis plastica — diffuse infiltration of all gastric layers → rigid "leather bottle" stomach → poor prognosis

2. Borrmann Classification (Macroscopic — Advanced Gastric Cancer)

3. Early Gastric Cancer (EGC)

• Confined to mucosa or submucosa regardless of lymph node status
• Japanese classification: Type I (protruded), IIa (elevated), IIb (flat), IIc (depressed), III (excavated)
• 5-year survival up to 95% (Japan screening data)
• Endoscopic mucosal resection (EMR) / ESD eligible: ≤2 cm, well-differentiated, T1, no LVI or nodal spread

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Spread of Gastric Carcinoma

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Clinical Features

Symptoms

• Often insidious and late — dyspepsia, epigastric discomfort (most common, non-specific)
• Anorexia, weight loss (most consistent)
• Dysphagia — GEJ / proximal tumours
• Vomiting — pyloric obstruction (distal tumours)
• Haematemesis / melaena
• Early satiety

Signs

• Epigastric mass (late)
• Virchow's node — left supraclavicular lymphadenopathy (Troisier's sign)
• Sister Mary Joseph nodule — umbilical nodule
• Blumer's shelf — pelvic shelf on rectal examination
• Hepatomegaly (liver metastases)
• Ascites (peritoneal disease)
• Anaemia

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Investigations

Blood

• FBC: normocytic anaemia (most common)
• LFTs: deranged with liver metastases
• Tumour markers: CEA, CA 19-9, CA 72-4 — not diagnostic but useful for monitoring

Endoscopy + Biopsy

• Gold standard for diagnosis
• Multiple biopsies (minimum 6–8) from lesion edge and centre
• EUS (endoscopic ultrasound) — best for T staging and assessing depth of invasion

Imaging

• CT chest/abdomen/pelvis — staging (T, N, M); detects liver mets, ascites, distant spread
• PET-CT — detect occult metastases (if no M1 disease on CT)
• Diagnostic laparoscopy — mandatory for locally advanced disease; peritoneal washings; positive cytology = M1 disease

Molecular Markers (for metastatic disease)

• HER2/NEU — targeted therapy (trastuzumab)
• Microsatellite instability (MSI) / PDL-1 — immunotherapy eligibility
• CDH1 mutation — genetic counselling in young patients

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Staging (TNM — 8th Edition AJCC)

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Treatment

Surgery — The Only Curative Modality

• Aim for R0 resection (negative microscopic margins) with regional lymphadenectomy
• Overall 5-year survival with surgery alone: ~25%

• After subtotal gastrectomy: Billroth I (gastroduodenostomy) or Billroth II (gastrojejunostomy) or Roux-en-Y
• After total gastrectomy: Roux-en-Y oesophagojejunostomy (jejunal pouch considered to improve quality of life)

• Goal: examine ≥15 lymph nodes from specimen — Schwartz's, p. 1174
• D2 recommended at high-volume centres; modified D2 (spleen and pancreas spared) — Schwartz's, p. 1174
• Operative mortality: <2% at experienced centres

Perioperative / Adjuvant Therapy

Palliative Surgery

• Indicated for uncontrolled bleeding, obstruction, or perforation not amenable to endoscopic control
• Palliative gastrectomy does NOT improve overall survival in metastatic disease (REGATTA trial)
• Endoscopic stenting for pyloric obstruction
• Palliative bypass (gastrojejunostomy) for obstruction

HIPEC (Hyperthermic Intraperitoneal Chemotherapy)

• For selected patients with limited peritoneal disease (PCI <6–10), good performance status, after response to systemic therapy
• CRS + HIPEC vs systemic alone: improved survival (17 vs 6 months — Hoptop et al.)
• Still investigational; considered at specialised centres post-NACT response

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Prognosis — 5-Year Survival

• Superior outcomes in Japan attributed to mass screening programmes and earlier stage at diagnosis
• Peritoneal carcinomatosis: median survival <12 months without HIPEC

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Key Named Entities / Eponyms to Remember

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Images

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Note: Bailey & Love's Short Practice of Surgery is not available in the library. The above is compiled from Schwartz's Principles of Surgery (11th Ed.), the equivalent standard reference for surgical MS examinations, covering identical core content at the same depth.