Gastric Cancer

What gastric cancer is

The stomach lining is exposed to acid, food, and in many people the H. pylori bacterium. Long-term inflammation can progress through a series of changes, chronic gastritis, atrophic gastritis, intestinal metaplasia, dysplasia, to cancer, over many years. Gastric cancer is less common in the US than in East Asia, Eastern Europe and Latin America, but rates of some types are rising in younger adults.

See stomach cancer for a plain-language overview of symptoms and what to expect.

Types of gastric cancer

Causes and risk factors

• H. pylori infection: the strongest risk factor, classed as a cause of cancer by the World Health Organization. Treating it lowers risk.
• Diet: high intake of salted, smoked, pickled and processed foods; low fruit and vegetable intake.
• Smoking and heavy alcohol use.
• Obesity: especially for cancers at the gastroesophageal junction.
• Age over 60 and male sex.
• Family history and inherited syndromes: hereditary diffuse gastric cancer (CDH1), Lynch syndrome, familial adenomatous polyposis, Peutz-Jeghers syndrome.
• Pernicious anemia and atrophic gastritis.
• Previous stomach surgery.
• Epstein-Barr virus in a subset of cancers.
• Ethnicity: higher rates in people of East Asian, Hispanic, Black, and Native American and Alaska Native descent in the US.

Symptoms

Early cancer may cause nothing or vague symptoms. Watch for:

• persistent indigestion or heartburn
• feeling full after small amounts of food
• loss of appetite and unintended weight loss
• upper abdominal pain or discomfort
• nausea and vomiting
• difficulty swallowing (cancers near the esophagus)
• tiredness and breathlessness from anemia
• black stools or vomiting blood
• in advanced disease: a swollen belly from fluid, a lump above the left collarbone, jaundice

Diagnosis

1. Upper endoscopy with biopsies: the key test. Modern endoscopy can detect subtle early cancers.
2. CT scan of the chest, abdomen and pelvis for staging.
3. Endoscopic ultrasound: measures how deep the tumor goes and nearby lymph nodes.
4. PET-CT in some cases.
5. Staging laparoscopy: keyhole surgery to look for spread to the abdominal lining before major surgery.
6. Tumor tests: HER2, PD-L1 (CPS), mismatch repair/microsatellite instability and Claudin 18.2 to guide treatment.

Stages

Treatment

Early cancer

Very early cancers confined to the lining can sometimes be removed by endoscopic resection (endoscopic mucosal resection or submucosal dissection) without surgery.

Localized cancer

• Surgery: partial (subtotal) or total gastrectomy with removal of nearby lymph nodes.
• Perioperative chemotherapy: commonly FLOT (a four-drug combination) given before and after surgery, which improves survival. Immunotherapy may be added in some settings.
• Chemoradiation in some cases, particularly at the gastroesophageal junction.

Advanced cancer

• chemotherapy combinations
• HER2-targeted therapy (trastuzumab) for HER2-positive tumors
• Immunotherapy (nivolumab, pembrolizumab) based on PD-L1 and mismatch repair status
• Claudin 18.2-targeted antibody (zolbetuximab) for eligible tumors
• palliative procedures: stents, radiotherapy for bleeding, and nutrition support

Living after gastrectomy

After stomach removal, people eat small, frequent meals, may experience dumping syndrome (sweating and diarrhea after sugary foods), and need lifelong vitamin B12 injections and monitoring of iron, calcium and vitamin D.

Prevention

• test and treat H. pylori infection, especially if you have a family history of gastric cancer
• do not smoke
• eat plenty of fruit and vegetables; limit salty, smoked and processed foods
• maintain a healthy weight
• people with CDH1 mutations are often offered preventive total gastrectomy
• endoscopic surveillance for people with extensive intestinal metaplasia or high-risk family history

Outlook

The 5-year relative survival for stomach cancer in the US is about 35% overall: roughly 75% when localized, about 35% with regional spread, and under 10% when distant. Survival is much higher in countries such as Japan and Korea, where screening detects more cancers early.

Frequently asked questions

What are the early signs of gastric cancer?

Early gastric cancer often causes no symptoms. When present, early signs include persistent indigestion, feeling full quickly, loss of appetite and mild upper belly discomfort. Weight loss, vomiting, black stools and anemia usually appear later.

What causes gastric cancer?

The main cause is long-term infection with the bacterium Helicobacter pylori. Other risk factors include smoking, a diet high in salted and smoked foods, obesity, older age, family history and inherited syndromes such as hereditary diffuse gastric cancer.

Is gastric cancer the same as stomach cancer?

Yes. Gastric is the medical word for stomach. Most gastric cancers are adenocarcinomas of the stomach lining. Other tumors in the stomach, such as GISTs and lymphomas, are treated differently.

How is gastric cancer treated?

Very early cancers can be removed endoscopically. Most localized cancers are treated with chemotherapy before and after surgery to remove part or all of the stomach. Advanced cancers are treated with chemotherapy combined with targeted therapy or immunotherapy based on tumor markers.

Can treating H. pylori prevent stomach cancer?

Treating H. pylori reduces the risk of gastric cancer, especially when done before precancerous changes develop. It also lowers the risk of a new cancer after early cancer treatment. Ask your doctor about testing if you have a family history.