Primary Gastric Lymphoma - Causes, Symptoms, and Treatment

What Is the Lymphatic System?

The lymphatic system comprises a group of tubes called lymph vessels. These lymph vessels carry a special type of thin fluid called lymph, which is watery in consistency from different parts of the body into the bloodstream. This lymph collects in between tiny spaces and contains nutrients like protein, fats, and some white blood cells known as lymphocytes. As the lymph advances in the lymphatic blood vessels, the lymph nodes help in filtering the microorganisms like viruses, bacteria, and other unwanted products from the bloodstream.

How Does Lymphoma Occur?

The majority of lymphoma occurs due to a flaw in the production of the lymphocyte, which is a type of white blood cell. Another reason could be a transformation of a single lymphocyte to a cancerous one. If it spreads to other lymph nodes such as bone marrow, spleen, and to other organs, it may lead to life-threatening complications. Most lymphomas arise inside the lymph nodes. If it arises from the outside, it is known as extranodal lymphoma. Primary gastric lymphoma is a common type of extranodal lymphoma. It is a subtype of non-Hodgkin's lymphoma.

Primary gastric lymphoma is a type of cancer that arises from the stomach. It mainly occurs in two forms, namely,

• Mucosa-associated lymphoid tissue.

• Diffuse large b cell lymphoma.

What Are the Signs and Symptoms of Primary Gastric Lymphoma?

The signs and symptoms of this disease are mostly vague and non-specific.

The most common symptoms include:

• Feeling of fullness after consuming less quantity of food.

• Nausea.

• Vomiting.

• Loss of weight.

• Tenderness in the abdomen.

• Indigestion.

• A general feeling of poor health.

• Bleeding from the stomach.

• A large mass can be felt in the stomach when touched and pressured.

• Sweating at night.

• Jaundice.

• Difficulty in swallowing, otherwise called dysphagia.

What Are the Risk Factors for Primary Gastric Lymphoma?

The risk factors include:

• Long-term immunosuppressant drug therapy (a treatment that suppresses the immune system of an individual).

• Human immunodeficiency virus infection.

• The presence of Helicobacter pylori infection.

What Are the Causes of Primary Gastric Lymphoma?

• The exact cause of this cancer is not known, but there is a strong association with Helicobacter pylori. It is a microorganism mostly found in the inner lining of the stomach and is known for its ability to cause ulcers.

• The mucosa-associated lymphoid tissue is formed due to chronic inflammation caused by the bacterium that arises from the lymphocytes present in the inner lining of the stomach. Helicobacter pylori is a microorganism that is generally present in the stomach of most humans but only some causes this cancer. This might be associated with the varied weakened immune response of individuals.

• Some individuals with mucosa-associated lymphoid tissue presented with chromosomal abnormalities like translocation (a piece of chromosome breaks and attaches itself to another chromosome). An example of this would be chromosomes 11 and 18, which have done translocation that showed poor response to antibiotics and difficulty in eradicating the Helicobacter pylori infection.

• The diffuse large B cell lymphoma is associated with mucosa-associated lymphoid tissue in a way in which It is said the diffuse large B cell lymphoma could be a more aggravated form of mucosa-associated lymphoid tissue. Some researchers believe that this could also be caused by the Helicobacter pylori infection.

What Is the Incidence of Primary Gastric Lymphoma?

• This lymphoma occurs primarily in older adults over 50 years of age. It is more prevalent in the age group of 60 to 70 years of age.

• Men are more commonly affected than women.

• It is more predominantly reported in Caucasians compared to African-Americans.

• Although it is the most common lymphoma present in the extranodal site, it accounts for only two to eight percent of all stomach ulcers.

How to Diagnose Primary Gastric Lymphoma?

A thorough clinical examination is necessary to detect certain signs and symptoms related to the type of lymphoma present.

• A blood test is necessary to check the number of white blood cells, red blood cells, and platelets present. It is also helpful in finding out the level of enzymes present. For example, the presence of the enzyme lactate dehydrogenase is found elevated in lymphoma that has rapid progression, which would require more intensive therapies.

• For individuals who have primary gastric lymphoma, a gastroenterologist will perform a procedure called upper gastrointestinal endoscopy, during which the doctor will place a thin, flexible tube into the mouth with a lens and a camera attached to it. The contents can be seen on a computer or an external device. A sample of tissue can also be taken to find out the presence of abnormal cells or microorganisms.

• Microscopic analysis of the affected tissues let the pathologists (a researcher or a scientist who studies the cause of the disease through microscopic findings) determine the size of the lymphocytic cell, the structure of the nucleus, and other components of the cell.

• Various imaging techniques like X-ray and computed tomography are used in the diagnosis of those lesions. In computed tomography, a computer and an X-ray are used to take cross-sectional images of the internal organs. This helps in seeing the extent of the lymphoma.

• Positron emission tomography is an important diagnostic test in lymphoma which uses nuclear medicine imaging technology. Generally, cancer cells metabolize sugar more rapidly than normal cells. In this technique, radioactive glucose is injected into the patients in which the cancer cells take up more quantity of glucose rapidly than normal cells, which causes the cancer cells to light up on the scan. It is useful in determining the extent of the spread of lymphoma.

• There is sometimes a chance for false positive results because positron emission tomography can also light up cells that are inflamed or which have an infection in the absence of cancer cells.

What Staging Method Is Used in Primary Gastric Lymphoma?

Staging needs to be determined when an individual is diagnosed with primary gastric lymphoma. The most common staging system used is the Lugano modification of an arbor staging system used for primary nodal lymphomas.

What Are the Various Treatment Options for This Lymphoma?

• The treatment options vary depending on the stage of the disease size of the tumor.

• Since the mucosa-associated lymphoid tissue is a slow-growing tumor, many doctors prefer the watch and weight strategy. In this strategy, the doctor will follow a patient with slow-growing cancer without giving treatment till the progression happens. This will be beneficial for some patients since the therapies can be avoided for many years or decades, which will also help in delaying the needs and side effects related to that treatment.

• For patients who are at an early stage of this disease, antibiotics can be prescribed. The initial treatment using antibiotics aims at eradicating the Helicobacter pylori bacteria. Regular follow-ups with blood tests and biopsies are necessary to check the presence of bacteria since mucosa-associated lymphoid tissue can recur if the patient gets re-infected with Helicobacter pylori infection.

• Radiation therapy can be recommended for patients who do not respond well to antibiotics. Radiation therapy uses radiation to kill the cancer cells using X-ray beams of a dose of 3000 cGy, although a dose of 2400 cGy is acceptable. A higher dose of 3600 cGy is used in the case of diffuse large B cell lymphoma. Most patients treated with radiation are cured.

• Surgery: In spite of surgery being successful in the past, it is now used only for cases that do not respond well to antibiotics, chemotherapy, or radiation.

• Chemotherapy: It is the use of different drugs alone or in combination to kill cancer cells. It is usually not needed for mucosa-associated lymphoid tissue. It is more frequently used for diffuse large B cell lymphoma patients. The most common chemotherapeutic regimen followed is R-CHOP, where R stands for Rituximab (biological therapy), and CHOP stands for Cyclophosphamide, Hydroxydaunorubicin, Oncovin, and Prednisone.

• Other therapies: These include symptomatic and supportive therapies. Medications for nausea and vomiting, pain, intravenous fluids for dehydration, antacids for ulcers, and stents to open up if there is any obstruction.

Conclusion:

Even though it is cancer, it is much more curable when treated at an early stage. Regular follow-ups and taking proper medications at the right time will aid in curing cancer. Following a healthy lifestyle and maintaining a balanced diet are also equally important in keeping unwanted microorganisms at bay.