Stomach cancer, also called gastric carcinoma, develops from an initially normal parietal cell (cell in the lining of the stomach) that multiplies uncontrollably and forms a mass called a malignant tumor.
More than 90% of the tumors that cause stomach cancer are adenocarcinomas, which means they develop from the superficial inner layer of the stomach called the mucosa. It is a slow-growing form of cancer that rarely develops before the age of 50.
The tumors may remain local for a long time before spreading to other layers of the stomach wall and invading nearby organs (pancreas, colon, spleen), or the cancer cells may enter the lymph nodes through the lymphatic and vascular pathways and then spread to other organs such as the liver and lungs (metastases).
Other types of stomach cancer, such as gastric lymphoma (which affects the lymphatic system), sarcoma (which affects muscle tissue), or gastrointestinal stromal tumor (which arises in the tissues of organs that support the digestive system), are much less common. They are not covered in this article.
There is no known cause of stomach cancer, but chronic inflammation of the stomach lining increases the risk, as in the case of Helicobacter pylori gastritis. Gastric cancer is also associated with long-term consumption of salty, smoked, and pickled foods, a diet low in fruits and vegetables, and smoking.
The earlier stomach cancer is diagnosed, the better the chances for cure. If it is still confined to the stomach lining, more than 50% of those affected survive more than 5 years. If it has spread to the lymphatic system, muscle layers, or other organs, the 5-year survival rate is less than 10%.
Who is affected?
It occurs unevenly. Globally, stomach cancer remains the second leading cause of cancer death, but it is the fourth leading cause of death in Europe, where it has been declining for 20 years. This decline in incidence concerns cancer of the antrum (distal stomach). However, for the cardia (proximal stomach), several studies indicate an increase in incidence.
This cancer is more common in populations with poor socioeconomic conditions or who rely heavily on pickling and smoking to preserve food. Japan (1/1000 population), China, and Korea are among the most affected countries.
In the US stomach cancer causes about 11,180 deaths per year. In developed countries, refrigeration has helped reduce the incidence of stomach cancer.
Symptoms of Stomach Cancer
At first, stomach cancer rarely causes specific, obvious symptoms. This makes it difficult to diagnose the disease at an early stage. However, it is common for a stomach tumor to cause the following symptoms:
- Feeling full and bloated, even if you haven’t eaten much
- Prolonged or recurrent indigestion
- Loss of appetite, disgust with food
- Abdominal pain, heartburn
- Unexplained weight loss
- Nausea and vomiting
- Bacterial infection
- Persistent diarrhea
- Vomiting of blood
- Difficulty swallowing.
These symptoms do not necessarily indicate the presence of a cancerous tumor. In fact, they may be signs of other more common problems, such as a stomach ulcer or an infection caused by bacteria. If you experience these symptoms, consult a doctor immediately so that he or she can perform the appropriate tests and determine the cause.
People at risk, risk factors, and prevention
Persons at risk
- People living in low socioeconomic circumstances, as is the case in many parts of Asia.
- People over the age of 50.
- Men are more likely to be affected by stomach cancer than women.
- People with chronic gastritis (inflammation of the stomach lining) or who have had an infection caused by Helicobacter pylori (H. pylori) bacteria are routinely tested during an upper endoscopy.
- People who have a family member with stomach cancer.
- People who have had stomach surgery.
- Certain rare diseases: Biermer’s disease.
- For reasons not known, studies have linked blood type A to a slightly increased risk of stomach cancer.
Several dietary factors have been considered, but little is known about their actual effects in the West.
- For Westerners, by far the main risk factor is inflammation of the stomach lining by the bacterium Helicobacter pylori, which is the main cause of stomach ulcers. However, in the vast majority of cases, infection with H. pylori does not lead to stomach cancer.
- Tobacco abuse.
- Too much salt from a diet high in smoked or salted meat or fish or products marinated in vinegar.
- A diet low in vegetables.
- Excessive consumption of nitrates and nitrites, which are used as preservatives in cured meats.
- Prolonged exposure to certain toxic industrial chemicals used in rubber processing and lead manufacturing.
These measures can help lower the risk of stomach cancer:
- Quit smoking
- Stop drinking alcohol
- Limit salt intake
- Limit consumption of smoked or salted meat or fish.
- Eat fiber, fruits, and vegetables regularly.
Medical treatment and complementary approaches
Treatment for stomach cancer varies according to the stage and malignancy (grade) of the cancer. Several therapies are often combined, including surgery, radiotherapy, and chemotherapy.
The choice of treatment is made in a multidisciplinary consultation (at least 3 different specialists should be present: gastroenterologist, oncologist, surgeon). A personalized treatment plan is drawn up for each person with stomach cancer, depending on the degree and extent of the disease.
Surgery is the only treatment that can remove the tumor and lead to a true cure. Sometimes it is not possible to remove the entire tumor because of its size or because the cancer has spread to other organs. In these cases, treatments are available to slow the progress of the disease and relieve symptoms.
Surgery involves removing the affected part of the stomach and nearby lymph nodes.
If the tumor is very superficial, endoscopic removal is possible. This involves removing the tumor without opening the abdomen but by inserting a flexible tube through the mouth.
Depending on the location of the tumor in the stomach, the surgeon removes part of the esophagus (proximal cancer) or the small intestine (distal cancer). There are 2 techniques: partial gastrectomy, for cancers of the distal part of the stomach, or total gastrectomy.
The surgeon performs a gastric anastomosis, sewing the two operated parts of the esophagus and stomach together to restore continuity. This allows a piece of the stomach to be retained, or an esophageal passage to be obtained, directly connecting the esophagus to the small intestine (anastomosis of the esophagus to the small intestine).
If the cancer is more extensive and affects other nearby organs, more extensive surgery affecting nearby organs, particularly the spleen, may be necessary.
After a gastrectomy, even a total gastrectomy, it is still possible to eat properly. However, because the stomach’s capacity is reduced the operated person must adjust his or her diet, for example, by eating fewer but more meals. Gastrectomy patients should also take certain dietary supplements, such as vitamin B12.
For stomach cancer, chemotherapy is usually used to kill the cancer cells.
For localized cancer, the medical team may give chemotherapy before surgery (pre-operative chemotherapy) to shrink the tumor, making it easier to remove later. Chemotherapy may also be given after surgery (postoperative chemotherapy), 6 to 8 weeks after surgery, to reduce the risk of recurrence.
In the case of metastatic cancer or inoperable tumors, chemotherapy is the treatment of choice. The goal is to limit disease progression, relieve symptoms, and improve quality of life. This is called palliative chemotherapy.
Many protocols and different therapeutic trials are underway to determine the best and most effective treatments.
Cellular microbiology has made it possible to better understand the mechanisms of tumor growth and develop targeted therapies. HER2 proteins have been identified in gastric cancer cells and metastases. In the case of a positive receptor, “monoclonal antibodies” are added to chemotherapy to block cancer cell division and development. They also stimulate the immune system to help destroy the cancer cells.
Chemotherapy can be given intravenously or orally. Chemotherapy drugs attack cancer cells, but they also damage some healthy cells. To give the body time to recover, chemotherapy is given in cycles. Side effects include nausea, vomiting, fatigue, loss of appetite, hair loss, and an increased risk of infections.
Radiation therapy is rarely used for stomach cancer. It may be used before, but usually after surgery, with or without chemotherapy, which is designed to enhance the effect of radiation. This is called “radiosensitizing chemotherapy.” It can also be used to relieve pain associated with a tumor that cannot be removed.
In this treatment, ionizing radiation is directed at a specific part of the body to destroy the cancer cells that have formed there. Since the high-energy rays also damage healthy cells, this therapy has several side effects that are more or less uncomfortable, depending on the person being treated. The patient may feel tired or notice that the skin in the irradiated area is red and sensitive. Radiation therapy for a tumor in the stomach may cause diarrhea, indigestion, or nausea. The side effects of radiation therapy go away after treatment when the healthy cells have regenerated.
Our Doctor’s Opinion
The incidence of gastric cancer has changed significantly over the past 25 years, probably due to socioeconomic changes, preservation methods (salts, nitrates, refrigeration), and changes in diet. In addition, recognition of genetic predisposing factors and systematic detection of Helicobacter Pylori infection has allowed for better screening and therefore earlier and more effective treatment. It is strongly recommended from the age of 50 onwards to see a general practitioner and then a gastroenterologist for any persistent digestive problems. Gastric endoscopy is a simple, non-invasive and effective detection procedure.