Stomach Cancer - Cause & Prevention

Stomach is a hollow J shaped organs situated in the upper abdomen. It is the main part of the digestive system where digestion of different nutrients takes place. Food from the mouth moves to the stomach through a muscular tube called as oesophagus. After digestion food from the stomach is passed to the small intestine. Stomach has five layers:

Inner layer: It secretes digestive juices for the digestion of food. Most stomach cancer starts in this layer of the stomach.
Sub mucosa: This layer supports the inner layer.
Muscular layer: Muscular layer helps in mixing of food by the contraction of muscles and helps to breakdown food into small particles.
Subserosa: This layer supports the outer layer of the stomach.
Outer layer: This layer provides a covering for the stomach.

Stomach cancer is also called as gastric cancer. In 2013, it is estimated that 21,600 Americans will be diagnosed to have gastric cancer and 10,990 will die due to it. It is common in older year after the age of 60. The most common type of gastric or stomach cancer is adenocarcinoma. Other malignant tumours include sarcomas, lymphomas and carcinoid tumours. Stomach cancer can be benign or malignant. Benign tumours can be removed easily and do not invade other tissues surrounding them. Malignant tumours are dangerous for life and can invade the nearby organs and tissues. They can easily spread to other parts of the body.

Stomach cancer begins in the inner layer of the stomach and slowly reaches the deeper layers. A stomach cancer can easily reach other nearby organs from the outer layer. A stomach cancer can also break from its original position and can spread to other parts through blood or lymph fluid.  The growth of the stomach cancer is prepyloric and often involves the greater curvature and rarely involves the lesser curvature.

Risk factors of stomach cancer
People having certain risk factors are more likely to suffer from stomach cancer than others. Some important risk factors that lead to the stomach cancer are discussed below:

Helicobacter pylori infection: H.pylori is a bacterium that is commonly found to infect the inner lining of the stomach. It is responsible for causing inflammation of the stomach lining as well as peptic ulcers. It is also known to increase the risk of stomach cancer. There is strong evidence that H.pylori infection is deeply responsible for the initiation and promotion of gastric carcinoma. The International Agency for Research on Cancer (IARC) classifies H. pylori infection as a cause of noncardia gastric carcinoma and low-grade B-cell mucosa-associated lymphatic tissue gastric lymphoma.

Smoking: Smoking is another important risk factor associated with stomach cancer. Studies have shown that people who smoke are more likely to develop stomach cancer than people who do not smoke.

Obesity: Obesity is thought to be an important risk factor for heart disease but a study has shown that insulin is not related to increased weight but it also stimulates the growth of cancerous cells and causes gastric cancer.

Lack of Physical activity: Studies have found that people who do moderate exercise or physical activity as at lower risk of gastric cancer as compared to people who are inactive physically. A multicenter (Columbia University, Fred Hutchinson Cancer Research Center, and Yale University) population-based collaborative case-control study is going on to identify risk factors that may lead to stomach cancer in the United States. Factors being evaluated include tobacco and alcohol use, medicinal and weight histories, use of selected medications, diet, family history of cancer and lifetime occupational history. Physical activity helps to maintain proper weight and also enables proper metabolism of the food nutrients.

Lack of Flavonoid intake: Flavonoids are plant substances and studies have shown that women who take high amount of flavonoid are at lower risk of developing stomach cancer than women who had smaller intake. Flavonoids are high in plant based foods such as fruits, vegetables, nuts, legumes, cereals, and whole grains.

Diet high in smoked, salted and pickled foods can lead to stomach cancer. Some medical conditions such as stomach polyps, long term inflammation of the stomach, vitamin B12 deficiency are also related to development of stomach cancer. People who eat a regular diet of highly salted food double their risk of stomach cancer according to a report published in the British Journal of Cancer. Dr Tim Key, an epidemiologist for Cancer Research UK which owns the British Journal of Cancer, says: "A study shows strong associations of stomach cancer with the intake of highly salted Japanese foods including salted fish and pickled vegetables.”

Symptoms of stomach cancer
Symptoms may not occur with benign stomach cancer but as soon as the cancer spread to other parts of the body, symptoms may appear. Some common symptoms of stomach cancer include:
·        Pain and discomfort in the stomach: The main symptom of an advanced case is pain which may be variable. Pain increases after food or manual pressure and is not relieved after vomiting. Pain may be referred to the back or upwards to the shoulder.
·        Difficulty in swallowing
·       Nausea and vomiting: Vomiting is large in quantity, contains coffee ground color blood and may be offensive due to the bacterial infection with H.pylori. Vomiting may occur immediately after eating food.
·        Weight loss due to loss of appetite
·        Bloating sensation in the stomach after eating food
·        Blood in the stool or vomiting of blood.
·        Loss of appetite: Appetite is lost early and it is associated with persistent nausea and weakness.
·        General fatigue occurs to loss of appetite and indigestion
·        A low fever is present due to infection

If you have any symptoms, immediately consult your physician for screening or testing for stomach cancer. Excessive bloating and belching can be the most important and early symptom of stomach cancer. This can further progressed to cause pain in the stomach. Several screening techniques, including barium-meal photofluorography, gastric endoscopy, and serum pepsinogen have been proposed as screening methods for the early detection of gastric cancer. Screening does not cause any impact on mortality from gastric cancer.

Prevention of stomach cancer
Screening is done for successful detection of the stomach cancer in the early stages. Certain important steps are given that may help you to reduce the risk of stomach cancer:

Avoid smoking and drinking alcohol: People who smoke should avoid smoking to prevent stomach cancer. Alcohol reduction is another preventive measure that may help in reduction of the stomach cancer.

Eat more fruits and vegetables and avoid spicy or junk food. Epidemiologic evidence from case-control and cohort studies suggests that increased intake of fresh fruits and vegetables are associated with decreased gastric cancer rates. Fruits and vegetables provide essential vitamins and minerals to human body and help to boost up the immune system.
Glutathione S-transferases are important in the detoxification of a wide range of human carcinogens. Studies have shown that people with the presence of this genotype are at lower risk of developing gastric cancer as compared to the people with null genotypes.

Cessation of smoking
The risk of stomach cancer decreases in smokers with cessation of smoking. Studies reveal that reduction of smoking or quitting of smoking reduces the chance of developing stomach cancer considerably.

Eradication of H.pylori infection
H.pylori is believed to be the most important cause of stomach cancer. Studies have shown that eradication of H.pylori infection can greatly reduce the risk of stomach cancer. A randomized controlled trial (RCT) showed that short-term treatment with amoxicillin and omeprazole reduced the incidence of gastric cancer by 39% during a period of 15 years.

According to Professor Dr Drs H.C. Meinhard Classen, co-chairman of the International Digestive Cancer Alliance, an organization that promotes screening, early detection and primary prevention of digestive cancers worldwide, stomach cancer can be prevented. Dr Classen said that cancer prevention starts with a healthy diet and regular exercise. The European Prospective Investigation into Cancer and Nutrition (EPIC) suggests that daily consumption of 500g of fruit and vegetables can decrease the incidence of cancers of the digestive tract by up to 25 per cent. Dr Classen also recommended 20 minutes of brisk exercise daily.

Dietary supplements
Dietary intake of certain nutrients such as beta carotene,vitamin A,vitamin E, selenium, vitamin C or foods that contain these compounds have greatly shown positive effect in reducing gastric cancer. A chemoprevention trial in China reported a statistically significant reduction in the gastric cancer mortality rate after supplementation with beta carotene, vitamin E, and selenium. These nutrients are available in natural foods such as fruits and vegetables. Therefore, a diet rich in above nutrients can greatly help in reducing the risk of stomach cancer.

The pigments and other chemicals that provide colour to the fruits and vegetables also contribute as they have cancer fighting properties. Citrus fruits, strawberries, kiwi, mango are best sources of beta carotene that is beneficial for fighting stomach cancer. Brazil nuts, seafood, oats, fish, some meats, wheat bran and brown rice are rich in selenium, which is another cancer fighter.

Tomatoes and tomato products contain lycopene which have been found to be effective against stomach cancer.

Natural herbs for stomach cancer
Increased consumption of garlic has been associated with modest but significant reductions in stomach cancer risk, according to an article published by UMMC. According to Pennsylvania State University, Garlic's preventive action against stomach cancer may come from anti-tumor effects of organosulfur compounds.

Green Tea
Epidemiologic studies show that green tea lowers cancer rates in people who regularly drink green tea, according to Penn State. Green tea is a rich source of a class of polyphenol compounds known as catechins, which exhibit strong antioxidant activity.

Asian Ginseng
According to Vanderbilt University, the pharmaceutical benefits of Asian ginseng are attributed to phytoestrogen compounds, known as ginsenosides, found in the herb.

Maitake (Grifola frondosa) is a big mushroom that grows in the mountainous region of northeastern Japan. This mushroom in its herbal extract form has been used to reduce stress and improve the immune system. Most importantly, it has been connected to increasing the body's natural cancer-fighting abilities.

Andrographis, which is also known as Andrographis paniculata and king of bitters, is found in the forests and wastelands of Asian countries like China and India. This herbal remedy has been used to fight infections, AIDS and the symptoms of cancer. It is believed that this herbal remedy has cancer fighting properties and it helps in destroying cancer cells. It helps by restricting stomach cancer cells from multiplying uncontrollably.