What is Gastric Lymphoma?
Gastric lymphoma, a type of stomach cancer, is responsible for about 5% of all stomach cancers but is the main type when it comes to lymphomas outside of lymph nodes. It accounts for 30-40% of these cases and 55-65% of lymphomas found in the digestive system. This group mainly consists of two types of cancers, MALT lymphomas and large cell lymphomas. Other types, like mantle cell lymphoma and follicular lymphoma, are much less common. It’s important to mention that over 90% of MALT lymphomas in the stomach are related to Helicobacter pylori infections. Therefore, treating this infection plays a big part in managing stomach lymphomas.
To diagnose stomach lymphomas, doctors may use a variety of methods, such as biopsy (removing a small piece of tissue to be examined under a microscope), ultrasound, CT scans, MRI scans, PET scans, and tests on body tissues or fluids to detect certain proteins (immunohistochemical testing). Your treatment plan might include antibiotics to treat the H pylori infection, biotherapy or immunotherapy (treatments that use your immune system to fight cancer), chemotherapy (drugs that kill cancer cells), and radiation therapy (using high energy waves to kill cancer cells).
What Causes Gastric Lymphoma?
Infection with a bacterium called H pylori in the stomach is one of the most common long-term infections worldwide. About half the world’s population has been infected or has had the infection before. This bacterium is found in up to 90% of people with a type of stomach cancer called gastric MALT lymphoma.
If not treated, an H pylori infection can cause ongoing inflammation and an increase in T-cells and B-cells in the stomach lining. The stomach lining usually doesn’t contain this type of tissue, but it can develop it when there’s long-term inflammation. This extra tissue can, unfortunately, turn cancerous, typically resulting in gastric MALT lymphoma. The good news is, in most cases this additional tissue goes away when the H pylori is treated.
Interestingly, those cases where the H pylori treatment doesn’t work are more likely to have altered or mutated genes. Some of these cases do transform into a more aggressive form of cancer called DLBCL, which typically has a worse outlook.
Several scientists have discussed a link between other infections and MALT lymphomas, including HIV, Epstein-Barr virus (EBV), hepatitis B virus, and human T-cell lymphotropic virus-1 (HTLV-1). EBV, in particular, hardly associates with MALT lymphoma, but may be involved in about 10% of gastric DLBCL cases. Other conditions such as celiac disease, inflammatory bowel diseases, and chronic immune weakening can also contribute to the development of gastric lymphoma.
Risk Factors and Frequency for Gastric Lymphoma
Primary gastric lymphoma, a type of stomach cancer, is not very common but its occurrence has been rising in the past 20 years. It is responsible for almost half of the lymphomas (a type of cancer) taking place outside the lymph nodes, but it makes up only around 5% of all stomach cancers.
About 40 years and older, the risk of developing this cancer notably increases, peaking in people in their sixties. Men are twice or triple as likely as women to get this particular cancer. This type of lymphoma is more commonly found in Western countries compared to Eastern ones.
There have been some debates in the medical community about the exact definition of primary gastric lymphomas. Most cases of this lymphoma are identified as B-cell, non-Hodgkin subtype, majority of which are called DLBCL of the stomach.
Signs and Symptoms of Gastric Lymphoma
Gastric lymphoma is a type of cancer that affects the stomach. The symptoms can greatly vary from person to person, but there are a few common ones. Patients often feel abdominal pain and get full quickly. Nausea, vomiting, and indigestion are also common. There are other symptoms such as fever, night sweats, and weight loss, but these are not as frequent. Some patients may have gastrointestinal bleeding, which can result in iron deficiency anemia or severe bleeding that can result in vomiting blood, the presence of bright red blood in stools, or black, tarry stools. Instances of obstruction and perforation of the stomach are rare. Upon a physical examination, a doctor may find nonspecific symptoms like tenderness in the upper abdominal area, a mass that can be felt in the upper abdomen, and swollen lymph nodes.
- Abdominal pain
- Feeling of fullness after eating only a small amount
- Nausea
- Vomiting
- Indigestion
- Fever
- Night sweats
- Weight loss
- Gastrointestinal bleeding
- Tenderness in the upper abdominal area
- A palpable mass in the upper abdomen
- Swollen lymph nodes
Testing for Gastric Lymphoma
Gastric lymphoma, a type of cancer, usually starts in an area of your stomach known as the gastric antrum. The best way to diagnose this condition is through a procedure called esophagogastroduodenoscopy (EGD), where a small flexible tube with a camera is used to see inside your stomach, followed by taking small tissue samples for further study under a microscope. This procedure helps visualize any irregular shallow erosions, ulcerations, enlarged folds in the stomach lining, or thickened walls of the stomach – all of which might indicate gastric lymphoma.
Once a person is diagnosed with gastric lymphoma, the next step is to figure out how far the cancer has spread – this is called staging. This often involves getting a CT scan of the chest, abdomen, and pelvis. An endoscopic ultrasound, a procedure where an ultrasound device on a thin tube is inserted down your throat to get a close-up of your stomach, can also help assess how deep the cancer has invaded the stomach wall and if it has affected nearby lymph nodes. However, this is not mandatory for the initial diagnosis.
In addition, doctors generally check for the presence of a bacterium called H pylori, which is found in up to 90% of gastric lymphoma cases. Detecting and treating this infection is a essential part of the overall treatment for gastric lymphoma. This can be done through several noninvasive and invasive tests, and successful eradication usually requires two negative test results.
Other diagnostic tests may include PET scans, mostly used to pinpoint locations for biopsy. However, they are not necessary for diagnosing gastric lymphoma. Tests such as bone marrow biopsies are also not commonly required. Initial tests for gastric lymphoma usually involve complete blood count to assess your overall health, studies of liver and kidney function, protein levels in blood, among other tests.
Finally, after diagnosis of a specific type of gastric lymphoma called “gastric MALT lymphoma,” doctors often check for a specific gene rearrangement, t(11;18), through a process known as fluorescence in situ hybridization (FISH). Confirmed by a specialist, its presence is crucial as it may influence treatment decisions.
Treatment Options for Gastric Lymphoma
Once diagnosed with gastric MALT lymphoma, a type of stomach cancer, your doctor will prescribe treatment to get rid of Helicobacter pylori (H pylori) bacteria. H pylori is a common cause of stomach infections, and its involvement in MALT lymphoma is significant. The specific treatment depends on your medical history, any allergies, and resistance to certain antibiotics in your area.
To confirm the elimination of H pylori, your doctor will conduct noninvasive tests, like a breath test or stool antigen test, about six weeks post-treatment. Even if tests had previously proven no presence of H pylori, your doctor would still recommend a two-week course of antibiotics together with proton pump inhibitors, a type of medication used to reduce stomach acid. Previous use of certain antibiotics, like macrolides, can make H pylori more resistant, potentially affecting the treatment’s effectiveness. It’s also been noted that gastric MALT lymphomas have shown a positive response to H pylori eradication therapy in over 75% of cases, even when the bacteria were not present during the lymphoma diagnosis.
For patients with early-stage low-grade gastric MALT lymphomas, an esophagogastroduodenoscopy (EGD)—a procedure where a tiny camera is passed down your throat to examine your digestive tract—is necessary 3-6 months after eradicating H pylori. The doctor examines your stomach closely and takes a tiny sample (biopsy) from different areas to check under a microscope using the Sydney protocol, a specialized evaluation method.
Full resolution of lymphoma symptoms in biopsy samples might take 1-14 months after H pylori treatment. Afterward, the patient will need to undergo EGD every six months for the first two years. The frequency can then reduce to once every 12-18 months.
Patients with gastric MALT lymphoma that tested negative for H pylori should be treated with involved-site radiation therapy (ISRT)—a type of radiation treatment that specifically targets the affected area—or given a drug called rituximab if radiation is unsafe due to the patient’s condition. Patients who show no change or incomplete eradication of the lymphoma after H pylori treatment can choose to have regular EGDs for monitoring, or they can opt for radiation or chemotherapy treatment.
But patients with higher-grade gastric MALT lymphoma, where the disease has spread to other parts of the body, are usually monitored without immediate treatment. If symptoms worsen, treatment options include chemotherapy with a drug called rituximab.
If the lymphoma worsens after the first-line treatment, there are other treatment options available, including combinations of rituximab, lenalidomide, and other specific inhibitors. You may also be advised to participate in clinical trials for new, potentially promising treatments.
Finally, surgery is typically reserved for emergency situations like uncontrolled bleeding, perforation, or blockage. Interestingly, radiation treatment has shown higher success rates compared to chemotherapy or immunotherapy in gastric MALT lymphoma patients.
Before starting treatment with rituximab, an immunotherapy drug, you should know that it can increase the risk of reactivating hepatitis B, so screening for hepatitis B and C, and HIV is recommended.
What else can Gastric Lymphoma be?
When a patient has symptoms that might suggest gastric lymphoma, their doctor needs to consider other possible conditions. These could include:
- Peptic ulcer disease
- Celiac disease
- Symptomatic gallstones (Cholelithiasis)
- Pancreatitis (inflammation of the pancreas)
- Hyperemesis (severe, persistent vomiting)
- Gastritis (inflammation of the stomach lining)
- Gastroparesis (slow emptying of the stomach)
- Inflammatory bowel disease
- Pancreatic cancer
- Acid reflux (Gastroesophageal reflux disease)
- Diverticulitis (inflammation or infection of small pouches in the digestive tract)
Surgical Treatment of Gastric Lymphoma
In the past, the first line of treatment for stomach cancer known as gastric lymphoma was usually removing it through surgery. However, now, surgery is mainly used for situations where there are complications such as a tear in the organ (perforation), blockage (obstruction), or unmanageable bleeding that can’t be controlled using a less invasive procedure known as endoscopic therapy.
If the gastric lymphoma keeps growing despite previous treatments such as eradication of H pylori bacteria, chemotherapy or immunotherapy, and radiation, an experienced cancer surgeon might consider surgical intervention. This can also be the case if the patient would rather not follow an expectant observation approach, which is monitoring their condition without any immediate treatment.
It’s important for the patient and their doctor to have a detailed conversation about this decision. They should consider both the risks, which are discussed in the ‘Complications’ section, and the potential benefits of surgery.
What to expect with Gastric Lymphoma
Gastric lymphomas, which are slow-growing cancerous tumors in the stomach, typically respond well to treatment, especially when discovered early. A specific type called low-grade gastric MALT lymphoma, which affects the inner and middle layers of the stomach wall, usually has an excellent prognosis. Up to 90% of people live for at least 10 years after diagnosis. In many instances, this type of cancer completely goes away with treatment aimed at eliminating H pylori – a type of bacteria often found in the stomach. But, if the cancer returns, it might be due to a new infection with H pylori.
However, if the cancer spreads deeper within the stomach wall or shows a specific genetic change known as t(11;18), it’s more likely to become a high-grade disease that cannot be cured with H pylori eradication therapy alone.
In such cases of high-grade gastric MALT lymphoma, despite the cancer’s typically slow development, chemotherapy, immunotherapy, or surgery may be required. A tool called the MALT-IPI (International Prognostic Index) is used to divide people with this type of cancer into three groups—low-risk, medium-risk, and high-risk—based on various factors. These include being age 60 or older, having a higher level of serum lactate dehydrogenase (a type of enzyme) in the blood, reaching advanced stages of the disease, and having symptoms at multiple sites on the internal stomach wall.
If no risk factors are found, the person is categorized as low risk. Among these patients, about 70% remain cancer-free for a minimum of five years, and 99% of them survive for at least five years. Medium-risk patients, with one risk factor, have a 56% chance of remaining free from cancer recurrence for five years and a 93% chance of surviving for at least five years. High-risk patients, with two or more risk factors, have poorer chances of surviving, with a 29% chance of remaining free from cancer recurrence for five years and a 64% survival rate over five years.
Possible Complications When Diagnosed with Gastric Lymphoma
When gastric MALT lymphoma, a type of stomach cancer, gets worse, it can cause more serious health problems. It might lead to bleeding in the stomach and intestines, tears in the stomach lining, and blockage at the stomach exit that prevents food from leaving the stomach. The lymphoma may also spread into nearby organs like the liver and pancreas, causing blockage of bile (a digestive fluid), infections, and pancreatitis, which is inflammation of the pancreas.
Radiation treatment carries its own risks, such as adhesions or abnormal connections between body parts, scarring, pancreatitis, and other problems caused by inflammation and scar tissue. Using the drug rituximab for immunotherapy can reactivate hepatitis B in patients who have been infected with it, possibly causing sudden severe liver damage and, although rare, even death. So, it’s crucial to check if the patient has been infected with hepatitis B before using rituximab. Surgery can cause complications such as bleeding, blockage at the stomach outlet, leaks at the site of surgical connection, adhesions, fistulas or abnormal connections between body parts, and infections.
Potential Complications:
- Bleeding in the stomach and intestines
- Tears in the stomach lining
- Blockage at the stomach exit
- Blockage of bile
- Infections
- Pancreatitis
- Adhesions
- Scarring
- Reactivation of hepatitis B
- Sudden severe liver damage
- Death (rare case)
- Leaks at the site of surgical connection
- Fistulas
Preventing Gastric Lymphoma
People diagnosed with gastric lymphomas, a type of cancer in the stomach, should be fully informed about the typical development and potential journey of their illness. They should also be aware of the various treatments available to them, which can vary greatly in intensity. At the easier end of the spectrum, doctors might suggest simply monitoring the situation, while more aggressive strategies could involve the use of chemotherapy, immunotherapy (treatment that uses certain parts of a person’s immune system to fight diseases), radiation, or surgery.
It’s also important for people with gastric lymphomas to understand the significance of sticking to their H pylori (a type of bacteria that can infect the stomach) eradication treatment. This treatment alone can reduce the severity of the illness and prevent it from turning into a more serious form. Consequently, it’s vital that patients adhere strictly to this proposed therapy strategy.
