- Gastric cancer, commonly referred to as stomach cancer, originates in the lining of the stomach and can develop in various regions of this organ.
- It is the sixth most common cancer and the fourth leading cause of cancer-related deaths globally.
- This disease is multifactorial, involving genetic, environmental, and lifestyle factors that contribute to its development.
- Gastric cancer typically begins with abnormal changes in the cells lining the stomach. The progression of gastric cancer often follows Correa’s cascade, a sequence starting from chronic non-atrophic gastritis to atrophic gastritis, intestinal metaplasia, dysplasia, and ultimately carcinoma.
- Gastric cancer can be classified based on histological characteristics, anatomical location, or molecular features.
- The most common type, adenocarcinoma, arises from glandular cells that produce mucus in the stomach lining. Histologically, adenocarcinoma is the most prevalent type, accounting for about 95% of cases.
- It is further divided into intestinal and diffuse subtypes. Intestinal adenocarcinomas are well-differentiated and follow a stepwise progression through precancerous stages. Diffuse adenocarcinomas are poorly differentiated, grow aggressively, and are harder to treat.
- Other subtypes include signet ring cell carcinoma, a subtype of diffuse adenocarcinoma characterized by mucin-filled cells, and squamous cell carcinoma.
- Anatomically, gastric cancers are categorized into cardia gastric cancer, which occurs in the upper stomach near the esophagus and is associated with obesity and gastroesophageal reflux disease (GERD), and non-cardia gastric cancer, found in other areas of the stomach, influenced by dietary habits and Helicobacter pylori infection.
- Several factors increase the risk of developing gastric cancer.
- Chronic infection with Helicobacter pylori is a major risk factor, initiating inflammation that progresses through Correa’s cascade.
- Epstein-Barr virus (EBV) infection is linked to some cases.
- Dietary habits, such as high consumption of salted, smoked, or pickled foods, increase risk due to carcinogenic effects of nitrates.
- Lifestyle factors like smoking significantly raise the risk for both cardia and non-cardia gastric cancers. Alcohol use amplifies this risk when combined with smoking.
- Genetic predisposition, including family history of gastric cancer and specific gene polymorphisms (e.g., TNF-α, IL-1), heightens susceptibility. Other factors associated with increased risk include obesity, low socioeconomic status, pernicious anemia, autoimmune gastritis, type A blood group, and prior gastric surgery.
- Early gastric cancer is often asymptomatic or presents vague symptoms such as indigestion, bloating, nausea, loss of appetite, or early satiety. Advanced stages may manifest more severe symptoms, including unexplained weight loss, vomiting (sometimes with blood), difficulty swallowing, fatigue, and persistent abdominal pain. Due to delayed symptom onset, gastric cancer is frequently diagnosed at advanced stages. Diagnostic methods include endoscopy with biopsy for histological examination and imaging techniques such as CT scans for staging. Molecular testing for biomarkers like HER2 or microsatellite instability (MSI) helps guide treatment strategies.
- Treatment options for gastric cancer depend on the stage and molecular characteristics of the tumor.
- Early-stage gastric cancer can often be treated with surgical resection (e.g., gastrectomy), offering curative potential. Endoscopic mucosal resection may be used for localized tumors.
- For advanced stages, combination therapies such as chemotherapy (e.g., fluoropyrimidines), radiation therapy, targeted therapies (e.g., trastuzumab for HER2-positive tumors), and immunotherapy (e.g., PD-L1 inhibitors) are employed. Palliative care focuses on symptom management to improve quality of life.
- Prevention plays a crucial role in reducing the incidence of gastric cancer. Measures include eradication of H. pylori infection, adopting a diet rich in fruits and vegetables while reducing salt intake, avoiding smoking and excessive alcohol consumption, and regular screening for high-risk individuals (e.g., those with family history or precancerous lesions).
- Gastric cancer remains a significant health concern worldwide, with its prevalence highest in East Asia due to dietary habits and high rates of H. pylori infection.
- Despite advancements in treatment modalities, outcomes remain poor for advanced cases due to late diagnosis. Enhanced awareness of risk factors and improved screening protocols are crucial for reducing mortality associated with this disease.
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