Non-Hodgkin’s lymphoma is cancer that originates in your lymphatic system, the disease-fighting network spread throughout your body. In non-Hodgkin’s lymphoma, tumors develop from lymphocytes — a type of white blood cell.
Non-Hodgkin’s lymphoma is more than five times as common as the other general type of lymphoma — Hodgkin’s disease. And Non-Hodgkin’s lymphoma has been increasing in incidence in the United States since the 1970s.
The good news is that although the incidence has increased, so has the survival rate. As with other cancers, the earlier the diagnosis, the greater your chance for a successful treatment of non-Hodgkin’s lymphoma.
Swollen, painless lymph nodes in your neck, armpit or groin areas are often the only sign of non-Hodgkin’s lymphoma in its early stages. Other signs and symptoms may include:
- Night sweats
- Weight loss
- Abdominal pain or swelling
- Chest pain, coughing or trouble breathing
- Extremely itchy skin
Normally, white blood cells called lymphocytes go through a predictable life cycle. Old lymphocytes die, and your body creates new ones to replace them. But in non-Hodgkin’s lymphoma, your body produces abnormal lymphocytes that continue to divide and grow uncontrollably. This oversupply of lymphocytes crowds into your lymph nodes, causing them to swell.
Doctors don’t know what exactly causes non-Hodgkin’s lymphoma. But researchers believe that activation of certain abnormal genes may be involved in the development of all cancers, including lymphomas.
B cells and T cells
Lymphocytes exist as either B cells or T cells. B cells fight infection by producing plasma cells, which in turn produce antibodies that neutralize foreign invaders. T cells are involved in killing foreign invaders directly. About 85 percent of non-Hodgkin’s lymphomas occur in B cells. The rest arise in T cells.
Non-Hodgkin’s lymphoma generally involves the presence of cancerous cells in your lymph nodes, but the disease can also spread to other parts of your lymphatic system. These include the lymphatic vessels, tonsils, adenoids, spleen, thymus and bone marrow. Occasionally, non-Hodgkin’s lymphoma involves organs outside of your lymphatic system.
In most cases, people diagnosed with non-Hodgkin’s lymphoma don’t have any obvious risk factors, and many people who have risk factors for the disease never develop it. Some factors that may contribute to your risk of non-Hodgkin’s lymphoma include:
- Immunosuppression. If you’ve had an organ transplant, you’re more susceptible because immunosuppressive therapy has reduced your body’s ability to fight off new illnesses.
- Infection. A number of infections appear to increase your risk of non-Hodgkin’s lymphoma. Having AIDS, in which your immune system is progressively weakened, also places you at higher risk. An infection with the bacterium Helicobacter pylori, which is known to cause ulcers, can cause an immune system response that raises your risk of non-Hodgkin’s lymphoma, particularly in the stomach.In Africa, infection with the parasite that causes malaria or the Epstein-Barr virus appears to raise the risk of a particular type of non-Hodgkin’s lymphoma, called Burkitt’s lymphoma.
- Chemicals. Certain chemicals, such as those used to kill insects and weeds, may increase your risk of developing non-Hodgkin’s lymphoma. More research is needed to understand the possible link between herbicides and insecticides and the development of non-Hodgkin’s lymphoma.
- Age. Non-Hodgkin’s lymphoma can occur at any age, but the risk increases with age. It’s most common in people in their 60s or older.
Your doctor may use these procedures to help diagnose non-Hodgkin’s lymphoma:
- Physical examination. Your doctor may examine not only your swollen lymph nodes but also your other lymph nodes to determine their size and consistency.
- Blood and urine tests. Usually, having swollen lymph nodes means you’re fighting an infection. Blood and urine tests may help your doctor rule out an infection or other disease.
- Imaging techniques. An X-ray or computerized tomography (CT) scan of your chest, neck, abdomen and pelvis may detect the presence and size of tumors. Magnetic resonance imaging (MRI) scans can help your doctor determine whether your brain and spinal cord are affected. Doctors also use positron emission tomography (PET) scanning to detect non-Hodgkin’s lymphoma.For a PET scan, a small amount of a radioactive tracer is injected into your body. This tracer is then absorbed by your tissues. Tumors are typically more metabolically active than other tissues, so they absorb more of the tracer. A PET scan also may be repeated after the first or second course of chemotherapy to see if the treatment is working. Tumors that respond to chemotherapy don’t absorb the tracer.
- Lymph node biopsy. Taking a sample of lymph node tissue for examination in the laboratory may reveal whether you have non-Hodgkin’s lymphoma and, if so, which type. This procedure may show the lymphoma to be growing slowly (low grade), at a moderate rate (intermediate grade) or rapidly (high grade). Knowing the growth rate of your tumor can help determine which treatment is best for you.
- Bone marrow biopsy. To find out whether the disease has spread, your doctor may request a biopsy of your bone marrow. This involves inserting a needle into your pelvic bones to obtain a sample of bone marrow.
Classifying the condition
Doctors classify non-Hodgkin’s disease into about 30 types. Besides the differentiation between B cell and T cell types of the disease, classification is based on several other factors. These include:
- Microscopic appearance
- Cellular genetic changes
- Cell size
- Staining patterns with specific antibody stains
- How the cancer cells group together
- How fast the cancer grows
Doctors also assign a stage (I through IV) to the disease, based on the number of tumors and how widely the tumors have spread.
Several factors affect the choice of treatment, including the type and stage of your lymphoma, your age, and your overall medical condition. The main treatment options include:
- Chemotherapy. Doctors use a combination of drugs — given orally or by injection — against fast-growing cancer cells. This combined treatment approach is used for intermediate- and high-grade lymphomas and advanced stages of low-grade lymphomas. A single drug may be used if you have a low-grade type of the disease.
- Radiation. High doses of radiation kill cancerous cells and shrink tumors. This treatment is for early stages of low-grade lymphomas. Sometimes, it’s used along with chemotherapy on intermediate-grade tumors or to treat specific sites, such as the brain.
- Stem cell transplantation. Lymphomas tend to be sensitive to chemotherapy. However, if lymphoma recurs, higher doses of chemotherapy may be necessary to treat the disease. The amount of chemotherapy that can be given is limited because of the damage chemotherapy does to your bone marrow. In order to avoid this serious side effect, healthy stem cells — those capable of producing new cells — are taken from your blood or bone marrow and frozen. After you undergo very high doses of chemotherapy to kill the lymphoma, the healthy stem cells are thawed and injected back into your body. This treatment is used primarily to treat intermediate- or high-grade lymphomas that relapse after initial, successful treatment.
- Observation. If your lymphoma appears to be slow growing, a wait and see approach may be an option. Slowly growing lymphomas with few symptoms may not require treatment for a year or more.
- Biotherapy. Rituximab (Rituxan) is approved by the Food and Drug Administration (FDA) for the treatment of B cell non-Hodgkin’s lymphoma. Rituximab is a type of monoclonal antibody that helps the immune system specifically target and destroy cancer cells. Rituximab is frequently used in combination with chemotherapy. It’s also sometimes given in tandem with radioimmunotherapy.
- Radioimmunotherapy. Two radioimmunotherapy drugs — ibritumomab (Zevalin) and tositumomab (Bexxar) — are currently FDA-approved. Radioimmunotherapy uses monoclonal antibodies combined with radioactive isotopes. The antibodies attach themselves to the cancer cells, while the added radiation helps destroy the cancer cells. Radioimmunotherapy is generally well tolerated; however, serious side effects, including reduced blood cell counts, hemorrhage and life-threatening infections, are possible with these medications. That’s why the FDA has approved their use only after other treatments have failed.
- Interferon therapy. Interferons are proteins that occur naturally in your body to help fight viral infection and regulate your immune system. Some research suggests that genetically engineered interferon can slow or stop the progression of some types of non-Hodgkin’s lymphomas. More studies are needed to determine whether interferon medications are an effective treatment for this