What is gastric (stomach) cancer?
Cancer that starts anywhere in the stomach is called gastric (stomach) cancer.
What is stomach?
The stomach is located in the upper abdomen and lies just below the lungs. It is a muscular bag and has three main parts:
(i) Cardia: Upper portion which connects the stomach with esophagus or food pipe.
(ii) Fundus/ Corpus: Middle part or body of the stomach, and
(iii) Antrum and Pylorus: The lower part of stomach.
Food that is swallowed is pushed through the esophagus into the stomach. The stomach mixes and breaks down the food by releasing gastric juices and digests the food so that our body can absorb it. Then the food moves into the small intestine for further digestion. Gastric juices are secreted by the glands in the wall of the stomach. They are acidic in nature.
Stomach continues to produce juices and proteins (enzymes), even when it is empty. To protect the stomach wall from the acid and the pepsin it also produces thick mucus.
Burden of the disease
- Stomach cancer is the 4th most common cancer in India and 3rd most common cancer in men.
- New cases in 2018: 57,394
New cases in males: 38,818
Are you at risk?
Exact risk factors for gastric cancer are not known. However, most of the gastric cancers are related to lifestyle factors.
I) Risk factors that you can modify
Risk factors include less consumption of fruits and vegetables, consumption of salty, smoked and poorly preserved foods, cigarette smoking, tobacco chewing, and radiation exposure.
Less consumption of fruits and vegetables may increase the risk of getting stomach cancer. The United Nations Food and Agricultural Organization (FAO) recommends at least 400 grams of fruits and vegetables per person per day (five serving of 80 g each day).
Eating foods that are high in salt can increase the risk of stomach cancer. Most of the salt you eat is in everyday foods such as pickles, bread, cereals and ready meals.
Risk of stomach cancer also increases if you eat lots of pickled vegetables which usually have high salt content.
A diet high in processed meat such as ham, bacon, salami and sausages has been linked to risk of stomach cancer.
Government of India recommends a limit of 90g of red and processed meat a day and advises to reduce it to 70g or less (cooked weight). This is about the same as about 2 sausages.
Smoking of food may lead to the release of cancer causing chemicals. Frequent intake of smoked foods has been associated with increased risk of cancers in the gastro-intestinal tract.
Smokers have about 1.5-2.5 times increased risk of stomach cancer than non-smokers. Tobacco chewing has also been linked to an increased risk of stomach cancer.
Heavy drinking increases the risk of stomach cancer.
It is a bacteria commonly found inside the lining of the stomach and the duodenum. It has been established as the root cause of most of the stomach ulcers and gastritis. H. pylori infection can be treated with antibiotics. If neglected, these peptic ulcers and gastritis can lead to stomach cancer and MALT (mucosa-associated lymphoid tissue) lymphoma of the stomach.
- Certain Medical Conditions
Long-term inflammation of the stomach, anemia due to vitamin B12 deficiency, stomach polyps, obesity etc may increase the risk of stomach cancer.
Toxins: Eating foods like groundnuts contaminated with a fungus called aflatoxin may increase the risk of stomach cancer.
II. Risk factors that are not modifiable
Age: Stomach cancer is more common in older people, especially those above 75 years.
Gender: Men are nearly twice as likely to get the disease compared to women.
Certain Genetic Conditions
• Family history of stomach cancer. Risk increases if you had/have a mother, father, sister, or brother who has had stomach cancer [30 ].
• Blood group A:Individuals with blood group A have increased risk for stomach cancer [ 31 ]
• Certain inherited syndromes such as Li – Fraumeni syndrome and Familial adenomatous polyposis (FAP) are associated with familial stoamch cancers.[ 32,33]
Are there screening tests for stomach cancer?
There is no routine screening test for gastric cancer. However, people with high risk of gastric cancer like those with inherited syndromes or chronic gastric atrophy or coming from areas with high number of cases may benefit from the following screening tests:
(1) Barium-meal photoflurography: A technique of x-ray of esophagus and stomach after the person drinks a liquid with barium (a metallic compound that coats the esophagus and stomach)
(2) Upper GI endoscopy
(3) Serum pepsinogen levels: Low levels suggest chronic gastric atrophy which is a risk factor for stomach cancer.
How can it be diagnosed?
Tests and procedures used to diagnose stomach cancer include:
• Upper GI endoscopy (Esophagogastroduodenoscopy or EGD): A thin, flexible lighted tube containing a micro camera at the end is passed down through the mouth into your stomach to look for signs of cancer. This lets the doctor examine the lining of your stomach. If any suspicious area is found, a small piece of tissue is taken from that site (biopsy) for laboratory examination.
Endoscopic ultrasound (EUS): A small transducer is placed on the tip of an endoscope. Sedation is given to the patient and the endoscope is passed down the throat and into the stomach. This allows the doctor to look at the layers of the stomach wall. If cancer is there, the doctor can check the nearby lymph nodes and other structures just outside the stomach to determine the extent of cancer spread. EUS can also be used to help in guiding a needle into a suspicious area to get a tissue sample (EUS-guided needle biopsy).
• Imaging tests: Computerized tomograpgy (CT) and a Barium swallow test (a special type of X-ray exam). Imaging is primarily used for staging in stomach cancer and also for post-treatment response assessment following Neoadjuvant Chemotherapy (NACT).
• Biopsy: A small tissue piece is taken from a suspicious-looking area found during endoscopy. Biopsy may also be taken from nearby lymph nodes or suspicious-appearing areas in other parts of the body to confirm spread of the stomach cancer.