Gastric cancer arises due to a synergistic interplay of microbial, genetic, environmental, and lifestyle factors. Understanding these determinants is crucial for prevention, screening, and early diagnosis.

1. Infectious Etiology

1. Helicobacter pylori infection is the most prominent risk factor for non-cardia gastric cancer. H. pylori induces chronic gastritis, mucosal atrophy, and intestinal metaplasia, mediated through virulence factors such as CagA, VacA, and BabA.

2. Epstein-Barr Virus (EBV) is implicated in approximately 10% of gastric cancers, often leading to distinct molecular signatures including PD-L1 overexpression, microsatellite instability (MSI), and CpG island methylator phenotype (CIMP).

3. Chronic viral or bacterial infections trigger persistent inflammation, oxidative stress, and genomic instability, creating a tumorigenic environment.

2. Dietary Factors

1. High intake of salted, smoked, pickled, and nitrite-rich foods is strongly correlated with gastric carcinogenesis due to formation of N-nitroso compounds.

2. Low consumption of fresh fruits, vegetables, and antioxidants increases susceptibility.

3. Excessive consumption of red and processed meat is linked with intestinal-type gastric cancer.

3. Lifestyle Influences

1. Tobacco use doubles the risk of gastric cancer, especially for proximal tumors.

2. Alcohol consumption, particularly heavy or chronic use, exacerbates mucosal injury and synergizes with smoking.

3. Obesity is strongly associated with gastroesophageal junction cancers through mechanisms involving chronic inflammation, reflux, and adipokine dysregulation.

4. Genetic and Familial Predisposition

1. Hereditary Diffuse Gastric Cancer (HDGC) caused by germline CDH1 mutations confers up to 70% lifetime risk of diffuse gastric carcinoma.

2. Lynch syndrome and Li-Fraumeni syndrome contribute to a higher predisposition.

3. Family history of gastric cancer increases risk two- to threefold, suggesting polygenic and environmental interactions.

5. Chronic Medical Conditions

1. Chronic atrophic gastritis from autoimmune gastritis or pernicious anemia promotes intestinal metaplasia.

2. Previous partial gastrectomy, particularly Billroth II reconstruction, increases long-term risk.

3. Barrett’s esophagus and chronic GERD predispose to proximal tumors.

Early gastric cancer is frequently asymptomatic or presents with subtle gastrointestinal disturbances, delaying diagnosis. Symptoms are often non-specific and may be mistaken for benign conditions such as gastritis or peptic ulcer disease.

Early Manifestations

1. Persistent dyspepsia, bloating, and epigastric discomfort.

2. Early satiety and postprandial fullness.

3. Mild nausea or vomiting, often overlooked.

4. Unintentional weight loss, fatigue, and anorexia.

Advanced Disease Symptoms

1. Progressive vomiting or gastric outlet obstruction.

2. Hematemesis or melena indicating bleeding tumors.

3. Palpable epigastric mass or Virchow’s node (left supraclavicular).

4. Ascites or hepatomegaly due to metastasis.

5. Obstructive jaundice from biliary spread.

Complication-Related Signs

1. Anemia leading to pallor, lethargy, and shortness of breath.

2. Severe pain from local invasion.

3. Cachexia due to chronic disease progression.

Accurate diagnosis is fundamental for treatment planning. Gastric cancer evaluation combines endoscopic, imaging, histopathologic, and molecular approaches.

1. Endoscopy

1. Esophagogastroduodenoscopy (EGD) is the primary diagnostic tool.

2. Biopsies confirm histological subtype and grade.

3. Advanced imaging with narrow-band imaging (NBI), magnifying endoscopy, or chromoendoscopy enhances detection of early lesions.

2. Histopathology and Molecular Testing

1. Distinguishes between intestinal-type and diffuse-type adenocarcinoma.

2. Immunohistochemistry for HER2, PD-L1, and mismatch repair proteins informs targeted therapy and immunotherapy eligibility.

3. Molecular profiling guides precision medicine, including gene mutations and MSI status.

3. Imaging Studies

1. CT scan of chest, abdomen, pelvis for staging and metastasis detection.

2. Endoscopic ultrasound (EUS) provides depth-of-invasion (T) and nodal (N) staging.

3. PET-CT evaluates occult distant metastases.

4. Laboratory Tests

1. CBC for anemia evaluation.

2. Liver function tests for metastasis assessment.

3. Tumor markers CEA, CA 19-9, CA 72-4 support follow-up and prognosis but lack diagnostic specificity.

5. Staging

1. AJCC TNM classification (8th edition) is used:

   1. T: Tumor depth.

   2. N: Regional lymph node involvement.

   3. M: Presence of distant metastasis.

Gastric cancer treatment is stage-specific and involves multidisciplinary care.

1. Surgical Treatment

1. Early-stage tumors: Endoscopic submucosal dissection (ESD) or laparoscopic partial gastrectomy.

2. Advanced tumors: Total or subtotal gastrectomy with D2 lymphadenectomy.

3. Palliative surgery: For obstruction, bleeding, or perforation.

2. Chemotherapy

1. Neoadjuvant chemotherapy reduces tumor size preoperatively.

2. Adjuvant chemotherapy eliminates residual disease postoperatively.

3. Common regimens: FOLFOX, CAPOX, ECF, FLOT.

3. Radiotherapy

1. Adjuvant chemoradiation improves outcomes in high-risk surgical patients.

2. Palliative radiotherapy alleviates pain, bleeding, or obstruction.

4. Targeted Therapy

1. HER2-positive tumors: Trastuzumab + chemotherapy.

2. VEGF inhibitors (Ramucirumab) for metastatic disease.

3. FGFR2 inhibitors and other emerging agents are under trial.

5. Immunotherapy

1. **PD

-1 inhibitors (Pembrolizumab, Nivolumab)** in MSI-high or PD-L1 positive tumors.

1. Part of clinical trial protocols for refractory disease.

6. Supportive Care

1. Nutritional support, pain management, and psychosocial counseling.

2. Palliative care for advanced, unresectable tumors to improve quality of life.

Primary Prevention

1. H. pylori eradication with antibiotics reduces cancer risk.

2. Healthy diet: High fruits, vegetables, fiber; low salt and processed meats.

3. Avoid tobacco and excessive alcohol.

4. Screening in high-risk populations** (Japan, Korea) using endoscopy.

Secondary Prevention

1. Endoscopic surveillance for patients with atrophic gastritis, intestinal metaplasia, or genetic risk.

2. Early detection programs in high-incidence countries reduce mortality.

Lifestyle Management

1. Weight management, exercise, and micronutrient supplementation improve resilience.

2. Psychological support, survivorship care, and patient education are integral to long-term outcomes.

1. Metastasis: Liver, lungs, peritoneum, bone.

2. Obstruction: Gastric outlet or pyloric obstruction leading to nausea, vomiting, and malnutrition.

3. Bleeding: Chronic anemia or acute hemorrhage.

4. Perforation: Medical emergency.

5. Treatment-related adverse effects: Cytopenias, neuropathy, mucositis, surgical complications such as anastomotic leak or infection.

Living with gastric cancer involves multifaceted care focusing on survival, quality of life, and psychosocial well-being:

1. Nutrition: Small, frequent, high-protein meals; supplementation as required.

2. Symptom management: Pain control, antiemetics, and palliative interventions.

3. Mental health support: Counseling, support groups, and cognitive coping strategies.

4. Physical activity: Tailored exercise to preserve strength and immunity.

5. Follow-up and monitoring: Regular imaging, endoscopy, lab tests, and adherence to treatment regimens.

6. Patient education: Awareness of symptoms, treatment side effects, and lifestyle modifications.

1. What is Stomach (Gastric) Cancer?

Stomach cancer, also called gastric cancer, is a disease in which malignant cells form in the lining of the stomach. It can develop slowly over several years and often affects the inner layer (mucosa) of the stomach before spreading to deeper layers and other organs.

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2. What causes Stomach Cancer?

The exact cause is not always known, but risk factors include:

1. Infection with Helicobacter pylori (H. pylori) bacteria

2. Dietary factors such as high salt intake, smoked or preserved foods

3. Tobacco and alcohol use

4. Chronic stomach inflammation or stomach polyps

5. Genetic mutations or family history of gastric cancer

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3. What are the common symptoms of Stomach Cancer?

Early stages may have few symptoms, but common signs include:

1. Persistent indigestion or stomach discomfort

2. Nausea or vomiting, sometimes with blood

3. Loss of appetite and unexplained weight loss

4. Swelling or pain in the abdomen

5. Difficulty swallowing (if tumor is near the esophagus)

6. Fatigue due to anemia

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4. How is Stomach Cancer diagnosed?

Diagnosis may involve:

1. Physical examination and medical history

2. Endoscopy (gastroscopy) with biopsy to examine stomach lining

3. Imaging tests such as CT scan, PET scan, or MRI to check spread

4. Blood tests to assess general health and detect anemia

5. Endoscopic ultrasound to evaluate tumor depth and lymph node involvement

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5. What are the treatment options for Stomach Cancer?

Treatment depends on the stage and location of the tumor:

1. Surgery: Partial or total gastrectomy (removal of part or all of the stomach)

2. Chemotherapy: Before (neoadjuvant) or after (adjuvant) surgery

3. Radiation therapy: Often combined with chemotherapy for better outcomes

4. Targeted therapy: For specific genetic markers in the tumor

5. Immunotherapy: In selected cases or advanced disease

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6. Can Stomach Cancer be prevented?

While not all cases are preventable, risk reduction strategies include:

1. Limiting intake of smoked, salty, and processed foods

2. Eating a diet rich in fruits and vegetables

3. Avoiding tobacco and limiting alcohol

4. Treating H. pylori infection early

5. Regular check-ups for those with family history or gastric polyps

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7. What are the possible complications of Stomach Cancer?

Complications may result from the cancer or its treatment:

1. Blockage of the stomach, causing vomiting or difficulty eating

2. Bleeding from the tumor, leading to anemia

3. Spread (metastasis) to liver, lymph nodes, or other organs

4. Side effects from surgery, chemotherapy, or radiation

5. Malnutrition due to reduced stomach function

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8. How is the prognosis determined?

Prognosis depends on:

1. Stage of cancer at diagnosis (early detection improves survival)

2. Tumor size and lymph node involvement

3. Patient’s age and overall health

4. Response to treatment
   Early-stage gastric cancer has a higher survival rate, while advanced stages have a lower prognosis.

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9. Can Stomach Cancer recur after treatment?

Yes. Recurrence is possible, especially in advanced-stage tumors. Regular follow-ups with imaging and endoscopy are essential to monitor for any recurrence. Lifestyle changes and adherence to treatment plans can reduce the risk.

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10. How can patients live with Stomach Cancer?

Living with gastric cancer involves:

1. Maintaining a balanced diet and proper nutrition

2. Managing symptoms and side effects with medical support

3. Regular follow-ups and monitoring for recurrence

4. Emotional and psychological support through counseling or support groups

5. Following treatment plans strictly and communicating openly with the healthcare team