Stomach Cancer

Stomach cancer, also known as gastric cancer, is a malignant tumor that develops in the stomach lining. This serious condition often remains asymptomatic in its early stages, making early detection challenging. Most stomach cancers are adenocarcinomas that arise from the cells lining the stomach. While relatively uncommon in the United States, stomach cancer remains a significant global health concern and requires prompt medical attention when symptoms develop.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. If you suspect you have stomach cancer or experience persistent digestive symptoms, consult a healthcare provider immediately.

Overview

Stomach cancer occurs when malignant cells develop in the tissues of the stomach wall. The stomach is a muscular, sac-like organ located in the upper abdomen that plays a crucial role in digestion. It produces acid and enzymes that break down food before it moves to the small intestine. When cancerous cells form in the stomach lining, they can grow and spread to nearby organs, lymph nodes, and distant parts of the body.

The most common type of stomach cancer is adenocarcinoma, which accounts for about 90-95% of all cases. These cancers develop from the glandular cells that line the inside of the stomach. Other less common types include lymphomas, gastrointestinal stromal tumors (GISTs), and carcinoid tumors. The location within the stomach where cancer develops can affect symptoms and treatment approaches.

Globally, stomach cancer is the fifth most common cancer and the fourth leading cause of cancer-related death. However, rates vary significantly by geographic region, with higher incidence in East Asia, Eastern Europe, and parts of Central and South America. In the United States, stomach cancer rates have declined significantly over the past several decades, partly due to improved food preservation techniques and reduced rates of H. pylori infection. Early-stage stomach cancer often has an excellent prognosis when detected and treated promptly, but advanced stages carry a more guarded outlook.

Symptoms

Early stomach cancer often produces no symptoms or only vague, nonspecific symptoms that can be easily attributed to other conditions. This silent progression makes stomach cancer particularly dangerous, as many cases are not diagnosed until the disease has advanced. Understanding the potential symptoms is crucial for early detection and treatment.

Early Symptoms

  • Heartburn - persistent indigestion or heartburn that doesn't respond to antacids
  • Nausea - feeling sick to the stomach, especially after eating
  • Burning abdominal pain - discomfort in the upper abdomen
  • Loss of appetite - decreased desire to eat or feeling full quickly
  • Bloating after meals - feeling overly full even after small portions

Progressive Symptoms

  • Difficulty swallowing - trouble swallowing food or liquids
  • Sharp abdominal pain - severe stomach pain that may worsen over time
  • Vomiting - especially if it contains blood or looks like coffee grounds
  • Diarrhea - frequent loose stools that may contain blood
  • Unintentional weight loss - significant weight loss without trying to lose weight

Advanced Symptoms

  • Blood in stool - tarry, black stools indicating upper gastrointestinal bleeding
  • Vomiting blood - hematemesis, which may appear bright red or coffee-ground colored
  • Severe fatigue - extreme tiredness due to anemia from blood loss
  • Jaundice - yellowing of skin and eyes if cancer spreads to the liver
  • Abdominal swelling - fluid accumulation in the abdomen (ascites)
  • Difficulty breathing - if fluid accumulates around the lungs

Systemic Symptoms

  • Persistent fatigue and weakness
  • Pale skin due to anemia
  • Swollen lymph nodes, particularly in the neck area
  • Loss of muscle mass and strength
  • Changes in bowel habits

Causes

The exact cause of stomach cancer is not fully understood, but researchers have identified several factors that contribute to its development. The disease typically results from a combination of genetic predisposition, environmental factors, and lifestyle choices that lead to DNA damage in stomach cells over time.

Helicobacter Pylori Infection

The most significant risk factor for stomach cancer is infection with Helicobacter pylori (H. pylori) bacteria:

  • H. pylori causes chronic inflammation of the stomach lining
  • Long-term infection can lead to gastric atrophy and intestinal metaplasia
  • These precancerous changes increase cancer risk significantly
  • Not everyone infected with H. pylori develops cancer
  • Certain strains of H. pylori are more carcinogenic than others

Genetic and Hereditary Factors

  • Hereditary diffuse gastric cancer (HDGC): Rare inherited syndrome caused by CDH1 gene mutations
  • Lynch syndrome: Hereditary cancer syndrome that increases stomach cancer risk
  • Family history: Having relatives with stomach cancer increases risk
  • Genetic polymorphisms: Variations in genes affecting inflammation and DNA repair
  • Blood type A: Slightly increased risk compared to other blood types

Dietary and Environmental Factors

  • High salt intake: Preserved, pickled, and salted foods
  • Nitrates and nitrites: Food preservatives that can form carcinogenic compounds
  • Smoked and processed meats: Contain potentially carcinogenic compounds
  • Low fruit and vegetable intake: Reduced antioxidant protection
  • Alcohol consumption: Chronic alcohol use increases risk

Pre-existing Medical Conditions

  • Chronic gastritis and gastric atrophy
  • Pernicious anemia and vitamin B12 deficiency
  • Previous gastric surgery or peptic ulcer disease
  • Gastric polyps, particularly adenomatous polyps
  • Ménétrier's disease (hypertrophic gastropathy)

Risk Factors

Several factors can increase an individual's likelihood of developing stomach cancer. Understanding these risk factors can help identify people who may benefit from screening or closer monitoring.

Non-Modifiable Risk Factors

  • Age: Risk increases significantly after age 55, with most cases occurring after 65
  • Gender: Men are twice as likely to develop stomach cancer as women
  • Ethnicity: Higher rates in Asian, Hispanic, and African American populations
  • Geographic location: Higher incidence in East Asia, Eastern Europe, and parts of South America
  • Family history: Having first-degree relatives with stomach cancer
  • Genetic syndromes: HDGC, Lynch syndrome, and other hereditary conditions

Modifiable Risk Factors

  • H. pylori infection: The most important modifiable risk factor
  • Diet: High salt, low fruit/vegetable intake, processed foods
  • Smoking: Increases risk, particularly for cancers in the upper stomach
  • Alcohol consumption: Regular heavy drinking
  • Obesity: Particularly for cancers affecting the gastroesophageal junction
  • Physical inactivity: Sedentary lifestyle

Medical Risk Factors

  • Chronic gastritis and gastric atrophy
  • Previous gastric surgery (gastrectomy)
  • Pernicious anemia
  • Gastric polyps, especially adenomatous types
  • Gastroesophageal reflux disease (GERD)
  • Autoimmune gastritis

Occupational and Environmental Factors

  • Exposure to certain chemicals in rubber and metal industries
  • Coal dust and asbestos exposure
  • Radiation exposure
  • Poor socioeconomic conditions and inadequate refrigeration

Diagnosis

Diagnosing stomach cancer requires a comprehensive approach combining medical history, physical examination, and various diagnostic tests. Early detection is crucial for optimal treatment outcomes, but the often subtle initial symptoms can make diagnosis challenging.

Medical History and Physical Examination

The diagnostic process begins with:

  • Symptom assessment: Detailed history of digestive symptoms
  • Risk factor evaluation: Family history, H. pylori infection status
  • Physical examination: Abdominal palpation for masses or tenderness
  • Lymph node examination: Checking for enlarged nodes

Laboratory Tests

Blood Tests

  • Complete blood count (CBC) to check for anemia
  • Liver function tests if metastases suspected
  • Tumor markers: CEA, CA 19-9 (not specific but may be elevated)
  • H. pylori testing (blood, stool, or breath test)

Imaging Studies

Upper Endoscopy (EGD)

  • Gold standard for stomach cancer diagnosis
  • Allows direct visualization of stomach lining
  • Enables tissue biopsy collection
  • Can assess extent of disease

CT Scan

  • Evaluates extent of disease and staging
  • Identifies metastases to liver, lungs, or other organs
  • Assesses lymph node involvement
  • Guides treatment planning

PET-CT Scan

  • Detects metabolically active cancer cells
  • Useful for staging and monitoring treatment response
  • May identify distant metastases

Specialized Tests

  • Barium swallow: X-ray study to visualize stomach structure
  • Laparoscopy: Minimally invasive surgery to assess spread
  • Endoscopic ultrasound: Evaluates depth of tumor invasion
  • Genetic testing: For hereditary cancer syndromes

Staging

Stomach cancer is staged using the TNM system:

  • Stage 0: Cancer confined to inner stomach lining
  • Stage I: Cancer has grown into stomach wall
  • Stage II-III: Cancer has spread to nearby lymph nodes or organs
  • Stage IV: Cancer has spread to distant organs

Treatment Options

Treatment for stomach cancer depends on the stage of disease, location of the tumor, patient's overall health, and personal preferences. A multidisciplinary team approach typically provides the best outcomes, involving gastroenterologists, oncologists, surgeons, and other specialists.

Surgical Treatment

Surgery is the primary treatment for stomach cancer when the disease is localized:

Subtotal Gastrectomy

  • Removal of part of the stomach
  • Preserves stomach function when possible
  • Suitable for tumors in the lower stomach
  • Lower morbidity than total gastrectomy

Total Gastrectomy

  • Complete removal of the stomach
  • Required for large tumors or those in the upper stomach
  • Esophagus connected directly to small intestine
  • Requires lifelong dietary modifications

Lymph Node Dissection

  • Removal of nearby lymph nodes
  • Important for staging and improving survival
  • Extent depends on tumor location and stage

Chemotherapy

Chemotherapy uses medications to destroy cancer cells:

  • Neoadjuvant: Given before surgery to shrink tumors
  • Adjuvant: Given after surgery to eliminate remaining cancer cells
  • Palliative: Used for advanced disease to control symptoms
  • Common drugs: 5-fluorouracil, cisplatin, oxaliplatin, docetaxel

Radiation Therapy

  • High-energy beams destroy cancer cells
  • Often combined with chemotherapy (chemoradiation)
  • May be used before or after surgery
  • Palliative radiation for symptom control

Targeted Therapy

  • Trastuzumab (Herceptin): For HER2-positive tumors
  • Ramucirumab: Anti-angiogenesis drug
  • Pembrolizumab: Immunotherapy for certain patients
  • Requires specific tumor testing for eligibility

Supportive Care

  • Nutritional support and dietary counseling
  • Pain management
  • Management of treatment side effects
  • Psychological support and counseling
  • Palliative care for advanced disease

Treatment by Stage

  • Stage 0-I: Surgery alone or with adjuvant therapy
  • Stage II-III: Combination of surgery, chemotherapy, and/or radiation
  • Stage IV: Palliative chemotherapy and supportive care

Prevention

While stomach cancer cannot always be prevented, several strategies can significantly reduce the risk of developing this disease. Focus on modifiable risk factors and maintaining overall digestive health.

H. Pylori Management

  • Testing and treatment: Screen for H. pylori infection and complete prescribed antibiotic therapy
  • Follow-up testing: Confirm eradication after treatment
  • Prevention of reinfection: Good hygiene and sanitation practices
  • Family screening: Test family members if one person is infected

Dietary Modifications

  • Increase fresh fruits and vegetables: Aim for 5-9 servings daily
  • Reduce salt intake: Limit processed, pickled, and salted foods
  • Choose fresh over preserved: Minimize smoked, cured, and processed meats
  • Adequate vitamin C: Citrus fruits and leafy greens
  • Antioxidant-rich foods: Berries, tomatoes, and colorful vegetables
  • Green tea: May have protective effects

Lifestyle Changes

  • Smoking cessation: Quit smoking and avoid secondhand smoke
  • Limit alcohol: Moderate consumption or abstinence
  • Maintain healthy weight: Regular exercise and balanced diet
  • Regular physical activity: At least 150 minutes of moderate exercise weekly
  • Food safety: Proper food storage and preparation

Medical Prevention

  • Regular medical check-ups for those at high risk
  • Treatment of gastritis and other stomach conditions
  • Genetic counseling for hereditary cancer syndromes
  • Screening programs in high-risk populations

Environmental Measures

  • Avoid occupational exposure to carcinogens
  • Proper ventilation in work environments
  • Safe drinking water sources
  • Adequate refrigeration of foods

When to See a Doctor

Seek immediate medical attention for:

  • Vomiting blood or coffee-ground material
  • Black, tarry stools indicating internal bleeding
  • Severe abdominal pain that doesn't improve
  • Signs of severe dehydration or shock
  • Difficulty swallowing that prevents eating or drinking

Schedule urgent appointment for:

Routine screening recommended for:

  • Individuals with family history of stomach cancer
  • People with known H. pylori infection
  • Those with chronic gastritis or gastric atrophy
  • Individuals from high-risk ethnic groups or geographic areas
  • People with hereditary cancer syndromes

Related Conditions

References

  1. National Cancer Institute. Gastric Cancer Treatment (PDQ®)–Health Professional Version. Updated 2023.
  2. American Cancer Society. Stomach Cancer. Updated 2023.
  3. Japanese Gastric Cancer Association. Japanese gastric cancer treatment guidelines 2021 (6th edition). Gastric Cancer. 2023;26(1):1-25.
  4. Ajani JA, et al. Gastric Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology. J Natl Compr Canc Netw. 2022;20(2):167-192.
  5. Smyth EC, et al. Gastric cancer. Lancet. 2020;396(10251):635-648.