Stomach is part of gastrointestinal tract that joins food pipe (esophagus) and small intestine. Stomach is located in upper part of the abdomen. It has mainly three parts, upper part- cardia, middle part- fundus and body and lower part- antrum and pylorus. Cancer involving any of these parts is called stomach (gastric) cancer. Stomach cancer was one of the leading causes of cancer-related deaths worldwide through most of the 20th century. It now ranks third in terms of cancer related mortality next to lung cancer and colo-rectal cancer. In India, stomach cancer is 4th most common cancer in general and 3rd most common cancer in men.
Who develops stomach cancer (Risk factors for stomach cancer)
There are many risk factors for development of stomach cancer, some are acquired and others genetic.
(A) Acquired factors:
1) Nutritional– high salt intake, high nitrate consumption, low intake of vitamin A and vitamin C, poor refrigeration of food, poor drinking water (well water). Poor method of food preparation like smoked food and salt cured food are also linked with stomach malignancy.
2) Occupational factors – rubber industry workers, coal workers
3) Cigarette smoking, tobacco chewing
4) Infection with Helicobacter pylori, Epstein-Barr virus
5) Radiation exposure
6) Previous stomach surgery for benign ulcers.
(B) Genetic Factors
- Family history of stomach cancer with involvement of first degree relative
- Anemia due to vitamin B12 deficiency
- Hereditary diffused gastric cancer
- Familial adenomatous polyposis
- Li-Fraumeni syndrome
- BRCA1 and BRCA2 mutations
(C) Obesity– elevated body mass index (BMI), high caloric intake, high glycemic load diet are associated with adenocarcinoma of distal esophagus and cardia of stomach.
Obesity also increases the gastro-esophageal reflux which is independently a risk factor for stomach cancer.
(D) Some precursor lesions such as gastric polyps, chronic atrophic gastritis, Menetrier disease are also associated with increased risk of gastric cancer. Some studies have found increased incidence of disease in blood group type A suggesting genetic etiology.
Some factors which have protective effects against stomach cancer have been explained such as eating raw fruits and vegetables, eating foods rich in vitamin C and E. Green tea, which contains large amount of phenols, could also be protective. Ideal body weight should be maintained to reduce chances of this malignancy.