```html

Gastric Cancer (Stomach Cancer)

What is Gastric Cancer?

Gastric cancer, also called stomach cancer, is a malignant tumor that arises from the lining of the stomach (the gastric mucosa). It develops when the normal cells that line the stomach undergo genetic changes that cause them to grow uncontrollably, form a mass, and invade surrounding tissues or spread (metastasize) to other organs.

Worldwide, gastric cancer is the fifth most common cancer and the third leading cause of cancer‑related death. The disease is more prevalent in East Asia (particularly Japan, South Korea, and China) but can occur in any population.

Common Causes

Gastric cancer rarely has a single identifiable cause. Instead, risk accumulates from a combination of environmental, infectious, dietary, and genetic factors. The most important contributors are:

• Helicobacter pylori infection – chronic infection damages the stomach lining and is responsible for up to 75% of cases (NIH).
• Diet low in fruits and vegetables – diets high in salted, smoked, or pickled foods increase risk.
• High intake of smoked or processed meats – contains nitrites that can form carcinogenic N‑nitroso compounds.
• Smoking – tobacco smoke doubles the risk of gastric cancer.
• Heavy alcohol consumption – especially when combined with smoking.
• Family history or inherited genetic syndromes – such as hereditary diffuse gastric cancer (CDH1 mutation), Lynch syndrome, or familial adenomatous polyposis.
• Chronic gastritis or gastric atrophy – long‑term inflammation predisposes to malignant transformation.
• Previous stomach surgery – especially partial gastrectomy for peptic ulcer disease.
• Obesity – excess body weight is linked to an increased risk of the intestinal type of gastric cancer.
• Occupational exposure – to dusts (e.g., coal, asbestos) or certain chemicals (e.g., rubber, metalworking fluids).

Associated Symptoms

Early gastric cancer often produces no symptoms, which is why many cases are diagnosed at an advanced stage. When symptoms do appear, they can be vague and overlap with common digestive problems. Typical manifestations include:

• Persistent indigestion or “bloating” after meals
• Unexplained weight loss (often >5% of body weight)
• Feeling of fullness after eating only a small amount (early satiety)
• Upper abdominal pain or discomfort that may be dull or burning
• Loss of appetite
• Vomiting, sometimes with blood (hematemesis) or material that looks like coffee grounds
• Difficulty swallowing (dysphagia) if the tumor blocks the outlet of the stomach
• Iron‑deficiency anemia (fatigue, pale skin) due to chronic bleeding
• Sudden, unexplained black, tarry stools (melena) indicating digested blood

When to See a Doctor

The following situations merit prompt medical evaluation, even if they seem mild:

• Persistent indigestion, heartburn, or nausea lasting more than 2–3 weeks.
• Unexplained weight loss of 5% or more within 6 months.
• Vomiting that contains blood or looks like coffee grounds.
• New‑onset anemia (especially iron‑deficiency) without an obvious cause.
• Dark, tarry stools or bright red rectal bleeding.
• Difficulty swallowing solid foods that gets progressively worse.
• Persistent abdominal pain that does not improve with over‑the‑counter medication.

Early evaluation can lead to detection when the cancer is still localized, dramatically improving treatment success rates.

Diagnosis

Diagnosing gastric cancer involves a stepwise approach that combines history, physical exam, imaging, and tissue sampling.

1. Medical History & Physical Examination

The doctor will ask about symptoms, risk factors (e.g., H. pylori infection, family history), and conduct a thorough abdominal exam looking for tenderness, masses, or enlarged lymph nodes.

2. Laboratory Tests

• Complete blood count (CBC) – to detect anemia.
• Comprehensive metabolic panel – to assess liver and kidney function.
• Serum tumor markers (e.g., CEA, CA 19‑9) – not diagnostic but can be useful for monitoring.

3. Imaging Studies

• Upper endoscopy (esophagogastroduodenoscopy, EGD) – Gold standard. A thin, flexible tube with a camera visualizes the stomach lining and allows for biopsy.
• Endoscopic ultrasound (EUS) – Determines depth of tumor invasion and assesses nearby lymph nodes.
• Contrast‑enhanced CT scan of the abdomen and pelvis – Stages disease, looks for spread to liver, peritoneum, or distant sites.
• Positron emission tomography (PET) – Helps locate metastases not seen on CT.
• Chest X‑ray or CT – Evaluates for lung involvement.

4. Pathology

Biopsy samples obtained during endoscopy are examined by a pathologist. The report includes:

• Histologic type (intestinal vs. diffuse, signet‑ring cells, etc.)
• Grade (how abnormal cells look)
• Presence of HER2 over‑expression (relevant for targeted therapy)
• PD‑L1 status and microsatellite instability (MSI) – important for immunotherapy decisions.

5. Staging

Staging follows the TNM system (Tumor size/extent, Node involvement, Metastasis). Accurate staging guides treatment planning and prognosis.

Treatment Options

Therapy is individualized based on tumor stage, location, patient’s overall health, and molecular characteristics. The main modalities are surgery, chemotherapy, radiation, targeted therapy, and immunotherapy. Supportive and “home” measures complement these treatments.

1. Curative‑Intent Surgery

• Partial gastrectomy – Removal of the tumor‑containing portion of the stomach with a margin of healthy tissue, followed by reconstruction (e.g., Billroth I/II, Roux‑en‑Y).
• Total gastrectomy – Complete removal of the stomach, used when the tumor involves most of the organ.
• Regional lymphadenectomy – Removal of nearby lymph nodes to reduce recurrence risk.

2. Chemotherapy

Often given before surgery (neoadjuvant) to shrink tumors, and/or after surgery (adjuvant) to eradicate microscopic disease. Common regimens include:

• FLOT (5‑fluorouracil, leucovorin, oxaliplatin, docetaxel)
• ECF/ECX (epirubicin, cisplatin, 5‑FU ± capecitabine)
• Capecitabine + oxaliplatin (CAPOX)

3. Radiation Therapy

Used in combination with chemotherapy (chemoradiation) for locally advanced disease or when surgical margins are positive.

4. Targeted Therapy

• Trastuzumab (Herceptin) – For HER2‑positive tumors (≈20% of gastric cancers).
• Ramucirumab – Targets VEGFR‑2, used in metastatic settings.

5. Immunotherapy

Checkpoint inhibitors such as pembrolizumab or nivolumab are approved for tumors with high microsatellite instability (MSI‑H) or PD‑L1 expression.

6. Palliative and Supportive Care

• Endoscopic stenting or gastro‑jejunostomy for obstruction.
• Blood transfusions or iron supplementation for anemia.
• Pain control, anti‑nausea medications, and nutritional counseling.

7. Home‑Based Measures

• Maintain a balanced diet rich in fruits, vegetables, and lean protein to support healing.
• Stay physically active as tolerated – walking or gentle resistance training improves energy and muscle mass.
• Quit smoking and limit alcohol; both impair treatment response.
• Join a support group or counseling to address emotional stress.
• Keep a medication diary and report side‑effects to your oncology team promptly.

Prevention Tips

While not all cases are preventable, lifestyle modifications and medical interventions can significantly lower risk:

• Eradicate Helicobacter pylori if infected – a short course of antibiotics and a proton‑pump inhibitor is highly effective (CDC).
• Eat a diet high in fresh fruits, vegetables, and whole grains; limit salty, smoked, and processed foods.
• Maintain a healthy weight (BMI 18.5–24.9).
• Avoid tobacco; seek cessation programs if you smoke.
• Limit alcohol to ≤2 drinks per day for men and ≤1 for women.
• Regular medical check‑ups for individuals with strong family history or known genetic mutations – consider surveillance endoscopy.
• Handle occupational dust and chemicals with proper protective equipment.
• Consider daily aspirin or NSAID use only under physician guidance; some data suggest reduced gastric cancer risk but the bleeding risk must be weighed.

Emergency Warning Signs

Key Take‑aways

• Gastric cancer is a serious disease often diagnosed late because early symptoms are subtle.
• Major risk factors include H. pylori infection, poor diet, smoking, excessive alcohol, and certain inherited gene mutations.
• Persistent indigestion, weight loss, vomiting blood, and anemia should prompt medical evaluation.
• Diagnosis relies on endoscopy with biopsy, imaging, and staging via the TNM system.
• Treatment is multimodal—surgery, chemotherapy, radiation, targeted agents, and immunotherapy—often combined for best outcomes.
• Prevention focuses on H. pylori eradication, healthy lifestyle choices, and surveillance for high‑risk individuals.
• Emergency signs such as vomiting blood or black stools require immediate care.

For personalized advice, always discuss your specific situation with a gastroenterologist or oncologist. Information in this article is sourced from reputable organizations including the Mayo Clinic, the CDC, the National Cancer Institute, and the World Health Organization.

```