Gastric Cancer (Stomach Cancer)

Category : Gastric Cancer | Sub Category : Gastric Cancer Posted on 2025-12-01 11:22:01

Stomach cancer (also called gastric cancer) is a malignant tumor that starts in the lining of the stomach. It is the 5th most common cancer worldwide and the 4th leading cause of cancer deaths (around 770,000 deaths per year as of recent 2024–2025

Types

- Adenocarcinoma: >90–95% of cases; starts in the mucus-producing cells of the stomach lining.

- Lymphoma: rare, arises from immune cells in the stomach wall.

- Gastrointestinal stromal tumors (GIST): start in the connective tissue/interstitial cells.

- Carcinoid tumors: neuroendocrine origin, usually slower-growing.

Major Risk Factors

- Helicobacter pylori (H. pylori) infection: the strongest risk factor; causes chronic gastritis → atrophic gastritis → intestinal metaplasia → cancer (responsible for ~70–90% of non-cardia cancers).

- Smoking: roughly doubles the risk.

- Heavy alcohol consumption.

- High-salt, smoked, or pickled food diets (common in East Asia).

- Family history / genetic syndromes:

  - Hereditary diffuse gastric cancer (CDH1 gene mutation)

  - Lynch syndrome, familial adenomatous polyposis

- Pernicious anemia / chronic atrophic gastritis.

- Previous partial gastrectomy (risk rises 15–20 years after surgery).

- Obesity (especially for cardia cancers in Western countries).

- Epstein-Barr virus (EBV) is linked to ~9% of cases worldwide.

Highest incidence countries (2024 data): South Korea, Japan, Mongolia, China, Eastern Europe. South Korea has the world’s highest rate (~40 per 100,000 in men) because of diet + aggressive screening programs.

Symptoms (often appear late)

Early stages → usually silent or vague

- Indigestion, heartburn, bloating after meals

- Mild upper abdominal discomfort

Later stages

- Unexplained weight loss

- Persistent abdominal pain

- Feeling full after small meals (early satiety)

- Nausea/vomiting (sometimes blood)

- Black stools (melena) or vomiting blood

- Fatigue, anemia

- Swallowing difficulty (if tumor is near the cardia)

How It’s Diagnosed

- Upper endoscopy (EGD) with biopsy: gold standard

- Endoscopic ultrasound (EUS): for staging depth and lymph nodes

- CT chest/abdomen/pelvis, PET-CT

- Staging laparoscopy (often done before surgery to rule out peritoneal spread)

Staging (TNM 8th edition simplified)

- Stage I: limited to stomach wall, curable with surgery alone (>80–90% 5-year survival)

- Stage II–III: deeper invasion or lymph nodes → surgery + chemo

- Stage IV: distant metastases (liver, peritoneum, lungs, bones) → median survival 10–16 months with modern treatment

Treatment (2025 standards)

Early (resectable)

- Endoscopic resection (ESD/EMR) for very early tumors

- Gastrectomy (total or subtotal) + D2 lymph node dissection (standard in East Asia, increasingly adopted in West)

- Perioperative (before + after surgery) FLOT chemotherapy (fluorouracil, leucovorin, oxaliplatin, docetaxel) is current standard in West

Locally advanced

- Neoadjuvant chemo or chemoradiotherapy → surgery

Metastatic (stage IV)

First-line:

- HER2-negative: FLOT or FOLFOX/CAPOX + nivolumab (anti-PD-1) or zolbetuximab (CLDN18.2-positive tumors) + chemotherapy

- HER2-positive: trastuzumab + chemotherapy ± pembrolizumab

Second-line and beyond:

- Ramucirumab + paclitaxel

- Trifluridine/tipiracil (TAS-102)

- Immunotherapy (PD-1 inhibitors) if MSI-high or high TMB

Survival Rates (approximate, U.S. SEER 2014–2020 & recent international data)

- Overall 5-year survival worldwide: ~25–30%

- Localized (stage I): 70–90%

- Regional (II–III): 30–40%

- Metastatic (IV): 5–7%

In high-screening countries like Japan and South Korea, overall 5-year survival exceeds 70% because >50% are diagnosed at stage I.

Prevention

- Test and treat H. pylori (especially in high-risk populations)

- Quit smoking

- Reduce salt-preserved foods, increase fruits/vegetables

- Screening endoscopy (national programs in Japan, South Korea for ages 40–50+)

If you have specific symptoms, family history, or are in a high-risk group, talk to a doctor about screening—early detection dramatically improves outcomes.