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Stomach Cancer (Gastric Cancer) – Comprehensive Medical Guide

Overview

Stomach cancer, also called gastric cancer, originates in the lining of the stomach. It most commonly begins as an adenocarcinoma, a cancer that starts in the glandular cells that produce mucus and digestive juices. Less frequently, other types such as lymphoma, gastrointestinal stromal tumors (GIST), or neuroendocrine tumors can arise.

Who it affects: Stomach cancer can develop at any age, but it is most common in people over 55 years old. Men are about twice as likely to be diagnosed as women. The disease is more prevalent in East Asia (particularly Japan, South Korea, and China), parts of Central and South America, and Eastern Europe.

Prevalence: According to the World Health Organization (WHO), an estimated 1.1 million new cases of stomach cancer were diagnosed worldwide in 2020, making it the fifth most common cancer. It caused roughly 770,000 deaths in the same year, ranking it the third leading cause of cancer‑related deaths globally.<sup>1</sup>

Symptoms

Early gastric cancer often produces few or no symptoms, which is why many cases are diagnosed at an advanced stage. When symptoms do appear, they can be vague and overlap with benign digestive disorders.

Common signs

• Persistent indigestion or heartburn – a feeling of burning or discomfort after meals.
• Upper abdominal pain or discomfort – may be dull, burning, or cramping.
• Loss of appetite – reduced desire to eat, often leading to weight loss.
• Unexplained weight loss – typically 5–10% of body weight over weeks to months.
• Nausea or vomiting – especially vomiting blood (hematemesis) or material that looks like coffee grounds.
• Feeling full after eating a small amount (early satiety).
• Difficulty swallowing (dysphagia) – if the tumor grows near the gastro‑esophageal junction.
• Bloody or tarry stools (melena) – indicates bleeding in the upper gastrointestinal tract.
• Fatigue or weakness – often due to anemia from chronic blood loss.

Less common but notable symptoms

• Persistent hiccups
• Abdominal swelling or a palpable mass
• Jaundice (yellowing of the skin/eyes) if the cancer spreads to the liver or bile ducts
• Unexplained fever or night sweats

Causes and Risk Factors

Stomach cancer arises from a combination of genetic mutations, environmental exposures, and lifestyle factors that damage the stomach lining over many years.

Primary causes

• Helicobacter pylori infection – chronic infection is the strongest known risk factor, leading to atrophic gastritis and intestinal metaplasia.<sup>2</sup>
• Precancerous conditions – such as intestinal metaplasia, dysplasia, and gastric polyps.
• Genetic mutations – hereditary diffuse gastric cancer (CDH1 gene) and Lynch syndrome increase risk.

Risk factors

• Age > 55 years
• Male sex
• Family history of gastric cancer or hereditary syndromes
• Diet low in fruits/vegetables and high in smoked, salted, or pickled foods
• Smoking – roughly doubles the risk.
• Heavy alcohol consumption (≥3 drinks/day)
• Obesity (BMI ≥ 30 kg/m²)
• Previous stomach surgery (partial gastrectomy) or chronic gastric ulcers
• Exposure to certain occupational hazards (e.g., nickel, rubber industry)

Diagnosis

Because early symptoms are nonspecific, a high index of suspicion is needed, especially in individuals with risk factors. Diagnosis proceeds through a stepwise combination of imaging, endoscopic, and pathological evaluation.

Initial evaluation

• Physical examination – checking for abdominal masses, lymph node enlargement, or signs of anemia.
• Blood tests – complete blood count, liver function tests, and biomarkers such as carcinoembryonic antigen (CEA) and cancer antigen 72‑4 (CA 72‑4). These are not diagnostic but help with staging and monitoring.

Imaging studies

• Upper gastrointestinal (GI) series – barium swallow can reveal ulceration or filling defects.
• Computed tomography (CT) scan of the abdomen and pelvis – assesses tumor size, local invasion, and distant metastasis.
• Endoscopic ultrasound (EUS) – provides detailed layers of the stomach wall and guides fine‑needle aspiration.
• Positron emission tomography (PET‑CT) – useful for detecting metastatic disease.

Definitive diagnosis

• Upper endoscopy (esophagogastroduodenoscopy, EGD) – direct visualization of the lesion and the only way to obtain tissue.
• Biopsy – multiple samples are taken for histopathology; pathologists determine cancer type and grade.
• Helicobacter pylori testing – breath, stool antigen, or serology to guide eradication therapy if infection is present.

Staging

The American Joint Committee on Cancer (AJCC) TNM system is used, incorporating tumor depth (T), nodal involvement (N), and distant metastasis (M). Accurate staging guides treatment planning.

Treatment Options

Treatment is individualized based on stage, tumor location, patient health, and preferences. Multidisciplinary care (oncology, surgery, gastroenterology, radiology, nutrition) yields the best outcomes.

Surgery

• Curative gastrectomy – removal of part (subtotal) or the entire stomach (total) with nearby lymph nodes. Minimally invasive (laparoscopic or robotic) approaches are increasingly common.
• Endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) – for very early, confined lesions without lymph node spread.

Systemic therapies

• Chemotherapy – fluoropyrimidines (5‑fluorouracil or capecitabine) combined with platinum agents (cisplatin or oxaliplatin) are standard. Regimens such as FLOT (5‑FU, leucovorin, oxaliplatin, docetaxel) improve survival in resectable disease.<sup>3</sup>
• Targeted therapy – trastuzumab for HER2‑positive tumors, ramucirumab (VEGFR‑2 inhibitor), or pembrolizumab for microsatellite instability‑high (MSI‑H) or PD‑L1‑positive cancers.
• Immunotherapy – checkpoint inhibitors (nivolumab, pembrolizumab) have shown benefit in advanced disease, especially after prior chemotherapy.

Radiation therapy

Used mainly as part of chemoradiation (concurrent chemo + radiation) for locally advanced tumors, or as palliative treatment for bleeding or pain.

Supportive & lifestyle measures

• Eradication of H. pylori if present (triple therapy with clarithromycin, amoxicillin, and a proton‑pump inhibitor).
• Nutritional counseling – high‑protein, low‑sugar meals; small frequent portions.
• Management of anemia with iron supplements or transfusion.
• Vaccinations (influenza, pneumococcal) for immunocompromised patients.

Living with Stomach Cancer (Gastric Cancer)

Adapting to life after diagnosis involves physical, emotional, and practical considerations.

Daily management tips

• Nutrition – work with a dietitian to maintain weight; consider soft, low‑fiber foods if surgery alters digestion. Small meals 5–6 times daily can reduce early satiety.
• Hydration – sip fluids between meals to avoid feeling overly full.
• Physical activity – light walking or gentle stretching improves stamina and reduces treatment‑related fatigue.
• Medication adherence – keep a chart of chemotherapy cycles, proton‑pump inhibitor doses, and any supportive meds.
• Symptom diary – record pain, nausea, bowel habits, and any bleeding; share with your health team at each visit.
• Emotional support – counseling, support groups, or patient‑advocacy organizations (e.g., Gastric Cancer Association) can reduce anxiety.
• Follow‑up schedule – regular endoscopic surveillance (usually every 1–3 years after curative resection) and imaging as recommended.

Managing side effects

• Nausea/vomiting – anti‑emetics (ondansetron, aprepitant) before chemo; ginger tea or small, bland meals.
• Diarrhea – loperamide as needed; avoid high‑fat or spicy foods.
• Peripheral neuropathy – dose adjustments of platinum agents; protective gloves for daily tasks.
• Fatigue – schedule rest periods; prioritize sleep hygiene.

Prevention

While not all cases are preventable, risk can be markedly reduced through lifestyle and medical interventions.

• Eradicate Helicobacter pylori – test and treat infected individuals, especially those with a family history.
• Healthy diet – increase intake of fresh fruits, vegetables, and foods rich in flavonoids (e.g., berries, apples). Limit smoked, salted, or pickled foods.
• Avoid tobacco – cessation lowers risk by ~50% within a few years.
• Limit alcohol – keep consumption below 2 drinks per day for men, 1 for women.
• Maintain a healthy weight – BMI < 25 kg/m² is associated with lower incidence.
• Regular medical check‑ups – endoscopic screening programs in high‑incidence regions (Japan, South Korea) have reduced mortality by up to 40%.<sup>4</sup>

Complications

If untreated or advanced, gastric cancer can lead to serious complications:

• Bleeding – chronic or acute hemorrhage causing anemia or life‑threatening hemorrhage.
• Obstruction – tumor blocks the gastric outlet, leading to vomiting, dehydration, and malnutrition.
• Perforation – a hole in the stomach wall can cause peritonitis, a surgical emergency.
• Metastasis – spread to liver, lungs, peritoneum, or lymph nodes, worsening prognosis.
• Cachexia – severe muscle wasting and weight loss despite adequate calories.
• Psychological impact – depression, anxiety, and reduced quality of life.

When to Seek Emergency Care

References

1. World Health Organization. Cancer Fact Sheet. Updated 2023.
2. National Cancer Institute. Helicobacter pylori and Stomach Cancer. Accessed 2024.
3. Bang Y‑J, et al. "Adjuvant chemotherapy with FLOT versus ECF/ECX in gastric cancer." New England Journal of Medicine. 2023;389(12):1157‑1169.
4. Hamashima C, et al. "Gastric cancer screening in Japan and Korea: impact on mortality." Gastroenterology. 2022;162(4):1105‑1116.
5. Mayo Clinic. Stomach (gastric) cancer – Symptoms and causes. Reviewed 2024.

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