Stomach Cancer

Stomach cancer is the malignant transformation of the lining of the stomach. It is classified into different groups depending on the type of tissue from which it originates. The most common type of stomach cancer is adenocarcinoma, which originates from the glandular tissues of the stomach.

Factors which can increase the risk of the disease are:

• Old age - It occurs more often in people aged more than 70
• Gender - Men have double the risk compared to women
• Race - There is increased risk in African-Americans and Asians
• Genetics and family history - Genetic abnormalities and family history of gastric cancer can double the risk
• Geography - Stomach cancer is more common in Japan, the Soviet Union, and parts of Central America and South America
• Blood type - Individuals with blood group A may be at increased risk
• Lifestyle factors - Factors such as smoking, consumption of alcohol, high salt diet, diet low in fruits and vegetables and consumption of smoked or nitrate-preserved foods may increase the risk
• Helicobacter pylori (H. pylori) infection of the stomach - H. Pylori is a bacterium that infects the lining of the stomach and causes chronic inflammation and ulcers
• Medical conditions - Health conditions like chronic gastritis, pernicious anemia, gastric polyps, intestinal metaplasia and prior stomach surgery increase the risk
• Occupational hazards - Exposure to hazardous material at work like coal mining, nickel refining, rubber and timber processing or asbestos manufacturing also increases the risk

Symptoms and signs:
In the early stages, usually it is asymptomatic or produces non specific symptoms like:

• Indigestion and stomach discomfort
• A bloated feeling after eating
• Mild nausea
• Loss of appetite
• Heartburn

In advanced stages, it may present with:

• Discomfort in the upper or middle part of the abdomen
• Blood in the stool (which appears as black, tarry stools)
• Vomiting or vomiting blood
• Weight loss
• Pain or bloating of the stomach after eating
• Weakness or fatigue associated with mild anemia

Investigations:
Initially, investigations like gastroscopy or biopsy is done to see the growth and to confirm if the tissue is malignant. After the confirmation, further investigations like CT scan, MRI and PET scan are done to know the extent to which cancer has spread.

Staging:
Staging is done depending on the tumor size, lymph nodes involved and the presence of metastasis (spread of the cancer).

Clinical staging:
Stage 0

• Limited to the inner lining of the stomach

Stage I

• Penetration to the second or third layers of the stomach (Stage 1A)
• Penetration to the second layer and nearby lymph nodes (Stage 1B)

Stage II

• Penetration to the second layer and distant lymph nodes
• Penetration to the third layer and nearby lymph nodes
• Penetration at all four layers but not the lymph nodes

Stage III

• Penetration to the third layer and distant lymph nodes
• Penetration to the fourth layer and nearby tissues
• Penetration to the fourth layer and nearby or distant lymph nodes

Stage IV

• Cancer has spread to nearby tissues and distant lymph nodes
• Cancer has metastasized to other organs.

Treatment:
The choice of treatment depends mainly on the size and location of the tumor, the stage of disease and general health. It involves surgery, chemotherapy and radiation therapy, usually in a combination.
In the early stages, surgery like endoscopic mucosal/submucosal resection is done and if the cancer is found to have a wider spread on histology, gastrectomy is performed followed by chemotherapy or radiation therapy.
In the advanced stages, chemotherapy or radiation therapy would be the treatment of choice, and in poor health only palliative care is provided.