Gastric (Stomach) Cancer

Gastric cancer (also called stomach cancer) makes up around 5% of all global cancers. It is the fifth most common cancer and the fourth leading cause of cancer death around the world.

While incidence rates have been declining globally over recent decades in some populations, the number of new cases and deaths continues to rise. Over half of all cases and nearly half of all deaths occur in East Asia, with China, Japan, and South Korea being the most affected.

Stomach cancer tends to grow slowly and often isn’t caught until later stages. H. pylori infection is the primary cause, causing an estimated 76% of cases globally. The CDH1 gene mutation is associated with hereditary diffuse gastric cancer (HDGC), a rare syndrome accounting for less than 3% of global gastric cancer cases.

What is gastric cancer?

The stomach sits in the upper abdomen and is attached to the esophagus and the small intestine. Its primary function is to break down food into a substance called chyme. The stomach holds the broken down food until it makes its way into the small intestine. Stomach cancer typically starts in the cells that line the inside of the stomach and it grows outward as it spreads. 

There are several parts of the stomach: The cardia (valve that connects to the esophagus), fundus (upper part), body (main part), antrum (lower part), and pylorus (a valve that connects to the small bowel). 

The gastroesophageal junction (GEJ junction - also called the esophagogastric junction (EGJ) or GE junction) is the place where the esophagus and stomach connect, and it’s the hotspot for a condition called Barrett’s esophagus. Uncontrolled heartburn can lead to this condition, which causes the lining of the esophagus to act more like stomach lining and causes cells to mutate, possibly becoming pre-cancerous. Many cancers in the U.S. occur in this area. 

Types of gastric cancer

Most stomach cancers are adenocarcinomas. These are cancers that begin in glands that line internal organs and make mucus and other fluids. 

Adenocarcinomas

Adenocarcinoma in the top of the stomach is called gastric cardia cancer. Non-cardia gastric cancer forms in the other sections of the stomach.

Intestinal vs. Diffuse Type

Gastric adenocarcinomas are also classified by how the cancer cells are arranged, using a system called the Lauren classification:

• Intestinal type: More common form, tends to develop slowly from precancerous changes in the stomach lining, and is more strongly linked to H. pylori infection, older age, and dietary risk factors. It is more common in men.
• Diffuse type (which includes signet ring cell carcinoma): Made up of loosely connected cells that spread throughout the stomach wall rather than forming a distinct tumor. It tends to be more aggressive, harder to detect early, and more common in younger patients and women. Associated with the CDH1 gene mutation and hereditary diffuse gastric cancer (HDGC).
  

Rare types of stomach cancer

A few other very rare types of stomach cancer include carcinoid tumors (neuroendocrine), gastrointestinal stromal tumors (GISTs), and lymphoma.

Staging gastric cancer

If you have stomach cancer, you need to know your stage. This helps you understand the size of your tumor, where the cancer is now, and the best treatment plan for your unique situation. 

Gastric cancer is staged on a scale from 0-4 (many researchers use roman numerals 0-IV) using the TNM staging system. In general:

• Stage 0 (carcinoma in situ): Abnormal cells are in the innermost layer of the stomach but have not grown into deeper tissue.
• Stage 1: Cancer has grown into the inner connective tissue or muscle layer of the stomach wall. It has not spread to lymph nodes (Stage 1A), or it is still in the inner layers but has spread to 1–2 nearby lymph nodes (Stage 1B).
• Stage 2: Cancer has grown deeper into or through the stomach wall, and/or has spread to a limited number of nearby lymph nodes, but has not reached distant organs.
• Stage 3: Cancer has grown through the stomach wall into nearby tissues or organs, and/or has spread to more regional lymph nodes. It has not spread to distant parts of the body.
• Stage 4 (also called "metastatic"): Cancer has spread to distant organs such as the liver, lungs, or abdominal lining, or to distant lymph nodes. It cannot be removed by surgery with curative intent.

What causes stomach cancer?

Risk factors put you at a higher risk of getting cancer. Some risk factors can be controlled with lifestyle changes, and others cannot. Older age, smoking, and obesity increase your risk of many cancers.

These are scenarios researchers have found that can increase your risk:

• H. pylori infection
• Diets with salty, smoked, and pickled foods
• Gastritis
• Stomach polyps or ulcers
• Epstein-Barr virus infection
• Pernicious anemia
• Gastroesophageal reflux disease (GERD)
• Family history of stomach cancer
• Certain genetic syndromes like familial adenomatous polyposis (FAP), Lynch syndrome, familial intestinal gastric cancer (FIGC), gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS), hereditary diffuse gastric cancer (HDGC) due to CDH1 mutation, juvenile polyposis syndrome, Li-Fraumeni syndrome, Peutz-Jeghers syndrome, and common variable immunodeficiency (CVID)
• Exposure to coal, metal, and rubber
• Type A blood

Veterans, those living in rural areas, and older adults are at a higher risk for stomach cancer.

Just because you have a risk factor, that doesn’t mean you will get cancer. 

H. pylori

76% of gastric cancers are attributable to H. pylori, making it the single most preventable cause of the disease. Eradicating H. pylori infection with antibiotics has been shown to significantly reduce gastric cancer risk.

Can you prevent stomach cancer?

There are several steps you can take toward reducing your risk of stomach cancer. If you discover that you have an H. pylori infection, or if you have stomach ulcers or gastritis, treat these conditions quickly.

Screening

Ask your doctor about screening if you have a family history of stomach cancer or inherited conditions that increase your risk. Upper endoscopy is a screening tool, and countries like Japan and South Korea have national screening programs that have dramatically reduced mortality. High-risk patients may benefit from individualized endoscopic surveillance.

As with every cancer, there are steps you can take to adopt a healthy lifestyle and reduce your overall cancer risk, such as maintaining a healthy weight, not smoking, and limiting or eliminating alcohol. 

Learn more about cancer prevention from the American Institute for Cancer Research.

What are some stomach cancer statistics? 

Based on GLOBOCAN 2022 data:

• An estimated 968,000 people were diagnosed with gastric cancer globally, and 660,000 died from the disease.
• Stomach cancer accounts for 4.9% of all new cancer cases worldwide, making it the 5th most commonly diagnosed cancer globally.
• It is the 4th leading cause of cancer death globally, responsible for 6.8% of all cancer deaths.

According to the World Cancer Research Fund:

• The 5th most common cancer worldwide; it is the 4th most common cancer in men and the 7th most common in women.
• China, Japan, and South Korea collectively account for approximately 75% of global cases, with China alone responsible for over 40% of the worldwide burden.

According to IARC:

• Incidence rates are on average twice as high in males as in females.
• Men in eastern Asian countries (particularly Japan, Mongolia, and South Korea) have the highest rates in the world.
• The annual global burden of gastric cancer is projected to increase to about 1.8 million new cases and 1.3 million deaths by 2040 (increases of roughly 63% and 66% respectively compared to 2020).
• 76% of all gastric cancers globally are due to H. pylori infection, making it the single most preventable cause of the disease.

According to the American Cancer Society: (In the U.S.)

• Stomach cancer mostly affects older adults; the average age at diagnosis is 68, and about 6 in every 10 people diagnosed are 65 or older.
  

What are my odds of surviving it?

Doctors use what’s called “survival statistics” to understand the likelihood of a patient beating the disease.

According to the National Cancer Institute, 37.9% of patients are alive five years after a gastric cancer diagnosis (in the U.S.).

Detailed survival statistics are based on where the cancer is located and if it has spread:

Localized

The cancer hasn’t spread

• 32.4% of cases
• 78.1% of patients are alive five years after diagnosis

Regional

The cancer spread to nearby lymph nodes

• 24% of cases
• 37.2% of patients are alive five years after diagnosis

Distant

The cancer has spread to lymph nodes and/or organs

• 35-37% of cases
• 7.5% of patients are alive five years after diagnosis
  

What types of tests should I expect to undergo?

Doctors typically use these tests to diagnose stomach cancer:

• Upper endoscopy
• Biopsy
  

Once you’ve been diagnosed, you may have these tests:

• Blood tests
• Ultrasound
• CT scan
• PET scan
  

Ask your doctor about these additional tests—ideally before you begin treatment.

• Biomarker testing
• Genetic testing

I’m facing a diagnosis: What are my next steps?

If you’re facing a diagnosis, the GI Cancers Alliance is here for you.  If you’re newly diagnosed, work with your doctor to create a treatment plan. 

Stomach cancer treatment plans may include:

• Surgery (possible partial or total gastrectomy)
• Chemotherapy
• Radiation
• Targeted therapy
• Immunotherapy

Gastrectomy

A total gastrectomy is the surgical removal of the entire stomach. This may be recommended for patients with advanced gastric cancer or for those with a CDH1 gene mutation who choose to have their stomachs removed so they can prevent cancer from developing.

Life after a total gastrectomy requires meaningful adjustments. Without a stomach, food passes directly from the esophagus into the small intestine, which affects how much you can eat at one time and how your body absorbs nutrients. Most patients need to eat smaller, more frequent meals and avoid high-sugar foods to prevent dumping syndrome, which is a condition that causes nausea, cramping, and dizziness after eating.

Lifelong vitamin B12 injections are typically required since B12 can no longer be absorbed through food alone. Iron, calcium, and vitamin D supplements are also often needed. Many patients adjust well over time, but the transition takes months. Many patients find major benefits from working closely with a dietitian experienced in post-gastrectomy care.

FLOT Protocol

The FLOT protocol is the standard chemotherapy regimen given to some patients before and after surgery. FLOT stands for the four drugs used: 5-fluorouracil (5-FU), leucovorin, oxaliplatin, and docetaxel. Patients receive four cycles of FLOT before surgery to shrink the tumor and reduce the risk of spread, followed by four more cycles after surgery to eliminate any remaining cancer cells. Clinical trials showed FLOT significantly improved survival compared to older chemotherapy regimens, and it is now the preferred standard of care in the US and Europe.

We strongly encourage you to get a second opinion from another trusted doctor so you feel confident moving forward.