Stomach Cancer

Stomach cancer (gastric cancer) develops in the lining of the stomach, often growing slowly over the years. While global incidence has declined, it remains a leading cause of cancer death worldwide, especially in East Asia. Here’s a concise yet comprehensive overview:

1. Types

• • Adenocarcinoma
    • 90–95% of cases.Arises from glandular cells in the stomach lining. Subtypes:
      • Intestinal:Gland-forming; linked to  pylori, diet.
      • Diffuse:Infiltrating cells (signet ring); aggressive, genetic links (e.g., CDH1 mutations).
    • Other Types:
      • Gastrointestinal Stromal Tumor (GIST):Starts in interstitial cells.
      • Lymphoma:MALT lymphoma (often  pylori-related).
      • Carcinoid/NETs:Neuroendocrine tumors.

2. Symptoms

• • Early:Often none or vague (indigestion, bloating).
  • Advanced:
    • Persistent abdominal pain/discomfort, unintentional weight loss.
    • Early satiety(feeling full after small meals), nausea/vomiting.
    • Dysphagia(if cardia tumor), melena (dark stools from bleeding), anemia.

        🚨 Red Flags: Persistent indigestion + weight loss or vomiting blood warrants urgent endoscopy

3. Risk Factors

• • Helicobacter pyloriInfection: #1 risk (causes chronic inflammation → precancerous changes).
  • Diet:High-salt foods (pickled/smoked meats), low fruit/vegetable intake, processed meats (nitrates).
  • Tobacco & Alcohol:Smokers have 2× higher risk.
  • Obesity & GERD:↑ Risk for proximal (cardia) tumors.
  • Genetics:
    • Hereditary Diffuse Gastric Cancer (HDGC):CDH1 gene mutation (↑ diffuse-type risk).
    • Lynch Syndrome, FAMMM.
  • Other:Pernicious anemia, chronic gastritis, prior stomach surgery.

4. Diagnosis

• • Endoscopy (+ Biopsy):
    • Gold standard.Visualizes tumors, takes tissue samples.
  • Imaging:
    • CT Chest/Abdomen/Pelvis:Staging (lymph nodes, metastasis).
    • Endoscopic Ultrasound (EUS):Assesses tumor depth (T-stage) and nodal spread.
    • PET-CT:Detects distant metastases.
  • Biomarker Testing:
    • HER2/neu:For targeted therapy (20% of cases).
    • MSI/PD-L1:Guides immunotherapy use.
  • pylori Testing:Breath, stool, or biopsy tests.

5. Treatment

            Localized Disease (Stages I–III)

• •     Surgery:
    • Subtotal or Total Gastrectomy: Removal of part/all stomach + lymph nodes (D2 dissection preferred in Asia).
    • Reconstruction: Roux-en-Y bypass.
  •    Adjuvant Therapy:
    • Chemoradiation (e.g., FLOT regimen: 5-FU/leucovorin/oxaliplatin/docetaxel) pre/post-surgery.

            Metastatic Disease (Stage IV)

• • Chemotherapy:
    • 1st-line: FLOT or FOLFOX/CAPOX.
    • HER2+ Tumors: Trastuzumab + chemo.
  • Immunotherapy:
    • PD-L1+ Tumors: Pembrolizumab ± chemo (1st-line).
    • MSI-H/dMMR Tumors: Pembrolizumab (any line).
  • Targeted Therapy:
    • Ramucirumab (VEGFR2 inhibitor) ± paclitaxel (2nd-line).
    • Fam-trastuzumab deruxtecan (HER2-low tumors).
  • Palliative Care:
    • Stents for obstructions, paracentesis for ascites, nutrition support.

6. Prognosis & Key Factors

• • Overall 5-Year Survival:~32% (lower in Western vs. Asian countries due to late diagnosis).
  • Favorable Factors:
    • Early stage (T1a), intestinal subtype,  pylorieradication, R0 resection.
  • Poor Prognosis:
    • Diffuse subtype, signet ring cells, peritoneal involvement, HER2-negative.

7. Prevention & Screening

• • pyloriEradication: Antibiotic therapy reduces risk by 30–50%.
  • Diet:Limit processed/salted meats; increase fruits, vegetables, fiber.
  • Screening (High-Risk Areas):
    • East Asia (Japan, Korea):National endoscopy programs (↓ mortality by 50%).
  • Genetic Testing:For CDH1 carriers (prophylactic gastrectomy considered).

Multidisciplinary care (surgery, oncology, GI, nutrition) is essential.