Stomach

Gastric cancer, also known as stomach cancer, develops when abnormal cells grow uncontrollably in the lining of the stomach.

Gastric cancer, also known as stomach cancer, develops when abnormal cells grow uncontrollably in the lining of the stomach. Over time, these cells can form a tumor and spread to other parts of the body.

Most gastric cancers are adenocarcinomas, arising from the glandular cells of the stomach lining. Less common types include lymphomas, gastrointestinal stromal tumors (GISTs), and neuroendocrine tumors.

At OncoClinic, we support you with appropriate diagnostics, clear explanations, and a personalized care plan tailored to your diagnosis, overall health, and goals.

Signs and symptoms

Persistent indigestion or heartburn
Upper abdominal pain or discomfort
Feeling full after eating small amounts of food (early satiety)
Nausea or vomiting
Loss of appetite
Unexplained weight loss
Fatigue or weakness
Other symptoms can include difficulty swallowing, black or bloody stools, vomiting blood, and signs of anemia such as shortness of breath or dizziness

Symptoms that persist or worsen over time should be evaluated by a healthcare professional.

Risk Factors

Age: Most cases occur after age 50
Gender: Men are affected more frequently than women
Family history and genetic predisposition: Including hereditary diffuse gastric cancer (CDH1 mutations)
Dietary factors: High intake of smoked, salted, or preserved foods and low consumption of fruits and vegetables
Smoking: Increases the risk of gastric cancer, particularly cancers of the upper stomach
Chronic stomach conditions: Chronic gastritis, gastric ulcers, intestinal metaplasia, and pernicious anemia
Previous gastric surgery: Partial gastrectomy for benign disease increases long-term risk
Helicobacter pylori (H.pylori) infection: The most important known risk factor, associated with chronic gastritis and intestinal metaplasia

Screening

Routine population-based screening for gastric cancer is not recommended worldwide, but practices vary by region. In countries with high incidence (such as Japan and South Korea), organized screening programs using endoscopy or radiographic methods are implemented and have been shown to improve early detection. In low-incidence regions, routine screening is not recommended for the general population.

Screening recommendations

Targeted surveillance may be considered for individuals at higher risk, such as:

Those with a strong family history or known genetic syndromes
Patients with premalignant gastric conditions
Individuals from high-incidence regions

Patients concerned about their risk should discuss screening options with a healthcare provider.

Diagnosis

Gastric cancer is usually diagnosed after symptoms prompt medical evaluation or when abnormalities are found during imaging or endoscopy.

Diagnostic evaluation typically includes:

Upper gastrointestinal endoscopy: The key diagnostic test, allowing direct visualization of the stomach and biopsy of suspicious lesions
Biopsy: Tissue samples are examined to confirm cancer and determine histologic type
Pathology and molecular testing: Including HER2 testing, MSI status, and PD-L1 expression to guide treatment decisions
Imaging studies: CT scans of the chest, abdomen, and pelvis to assess disease extent

Additional tests may be used depending on clinical finding

Staging

Once gastric cancer is confirmed, staging determines how far the disease has spread and guides treatment planning.

Staging evaluation may include:

CT scan: CT scans of the chest, abdomen, and pelvis
Endoscopic ultrasound (EUS): To assess tumor depth and local lymph node involvement
PET/CT scan: Used in selected cases to detect distant metastases
Diagnostic laparoscopy: In some patients, to identify small peritoneal metastases not seen on imaging

Gastric cancer staging

Gastric cancer is staged from Stage I to Stage IV:

Stage I: Cancer confined to the stomach wall
Stage II–III: Deeper invasion and/or spread to regional lymph nodes
Stage IV: Spread to distant organs or the peritoneum

Treatment and Procedures

At OncoClinic, gastric cancer care is delivered through a multidisciplinary, patient-centered approach. Treatment plans are individualized based on tumor stage, molecular characteristics, and overall health.Treatment options may include:

Surgery: Surgical removal of part or all of the stomach is the main curative treatment for localized gastric cancer, often combined with lymph node dissection.

Chemotherapy: Used before surgery (neoadjuvant), after surgery (adjuvant), or as the main treatment in advanced disease.

Radiation therapy: May be used in selected cases, often combined with chemotherapy, particularly for locally advanced disease.

Targeted therapy: Includes treatments such as HER2-targeted agents for tumors with specific molecular features.

Immunotherapy: Used in selected patients with advanced or metastatic gastric cancer, based on molecular and biomarker testing.

Combined treatment strategies: Many patients benefit from a coordinated combination of surgery, chemotherapy, radiation therapy, targeted therapy, or immunotherapy.

Palliative and supportive care: Focused on symptom relief, nutritional support, and quality of life at all stages of disease.