Lymphoma is a cancer of the lymph (or lymphatic) system. It is part of the immune system. It collects and destroys invading organisms, such as bacteria and viruses, and abnormal cells. It protects the body from infection and disease.
The lymph system is a network of tissue, vessels, and fluid (lymph). It includes:
- Lymph. This clear fluid carries white blood cells, especially lymphocytes, though the lymph system. White blood cells help fight infection.
- Lymph vessels. These thin tubes carry lymph from different parts of the body to the bloodstream.
- Lymph nodes. These small masses of tissue store white blood cells. They also help remove bacteria and other substances from the lymph. Lymph nodes are located in the neck, underarms, chest, abdomen, pelvis, and groin.
Lymph tissue also resides in the spleen, thymus gland, tonsils, bone marrow, and digestive system.
Lymphatic tissue is composed mainly of lymphocytes. There are two main types of lymphocytes:
- B cells make antibodies that kill bacteria and viruses.
- T cells fight infections using other chemicals and processes.
Lymphoma starts when a lymphocyte changes into an abnormal cell that begins dividing out of control. These abnormal cells often form masses (tumors) in lymph nodes and elsewhere. Because lymph tissue is located throughout the body, lymphoma can begin almost anywhere. It can spread to almost any tissue or organ.
The two main types of lymphoma are Hodgkin disease (Hodgkin lymphoma) and non-Hodgkin lymphoma. There are about 30 different types of non-Hodgkin lymphoma.
Hodgkin disease can affect lymph tissue anywhere in the body. It can also spread from lymph tissue to other organs. Hodgkin disease usually affects people in their late 20s or older than 50. Males get the disease more often than females. Whites are affected more often than people of other races.
Most lymphoma is non-Hodgkin lymphoma. In adults, non-Hodgkin lymphoma affects males more than females. It often occurs between the ages of 60 and 70. Whites are affected more often than people of other races.
Non-Hodgkin lymphoma has become more common in the past few decades. This may be related to the rise in the number of people who have a suppressed immune system, such as people infected with human immunodeficiency virus (HIV) and those who have had an organ transplant and need to take drugs that alter the immune system.
Age is a major determinant of the type of non-Hodgkin lymphoma. Slow growing lymphomas (low grade) are more likely to occur in an older person. Fast growing (high grade aggressive) non-Hodgkin lymphomas usually affect children and young adults. Lymphomas are classified by the specific characteristics of the cancer cells and the parts of the body affected.
The main symptom of both Hodgkin and non-Hodgkin lymphomas is swollen lymph nodes in the neck, under the arms, or in the groin. Other symptoms include:
- night sweats
- extreme fatigue
- unexplained weight loss
Because swollen lymph nodes caused by lymphoma usually are painless, they may get larger over a long time before the person notices. Also, fever may come and go for several weeks. Even the unexplained weight loss may continue for months before the person sees a doctor.
Diagnosis usually begins with a physical exam. Your doctor will check for swollen lymph nodes and organs throughout your body. He or she will look for general signs of disease. You will be asked about your health habits and past illnesses and treatments, too.
If your doctor suspects lymphoma, he or she will order blood tests to check the numbers and appearance of your blood cells (red cells, white cells and platelets). Sometimes the diagnosis can be made with a special blood test called flow cytometry. This test is a way to sort and identify the different types of cells in the blood, including cancerous lymph cells.
Your doctor will likely recommend a lymph node biopsy to confirm the diagnosis. In this test, all or part of a lymph node is removed using a needle or during minor surgery. A specialist then views the tissue under microscope to check for lymphoma.
You may also need other tests, such as CT scans or an MRI of your chest and abdomen and/or a positron emission tomography (PET) scan. Often a bone marrow biopsy is performed. During this test, your doctor removes a sample of bone and liquid bone marrow from the hipbone or breastbone. The samples are analyzed for signs of cancer.
These additional tests are done to determine the stage of lymphoma. The stages range from Stage I, in which the cancer is limited to one area, such as one lymph node, to Stage IV, in which the cancer is growing in many lymph nodes throughout your body or in the bone marrow or other organs.
Occasionally, laparoscopic surgery is done to help to determine the cancer's stage. In this procedure, your doctor makes a small incision in your abdomen, and uses a thin, lighted tube (a laparoscope) to see if cancer has spread to any internal organs. Small pieces of tissue also may be removed and examined under a microscope for signs of cancer.
Hodgkin lymphoma can often be cured.
The duration of non-Hodgkin lymphoma varies. Some forms of non-Hodgkin lymphoma are slow-growing. In these cases, treatment may be postponed until symptoms appear.
In general, both Hodgkin and non-Hodgkin lymphoma will continue to worsen unless it is treated.
There is no definitive way to prevent lymphoma. But you may be able to lower your risk by taking precautions to avoid becoming infected with HIV.
Radiation is the traditional treatment for Hodgkin disease that is localized to one group of lymph nodes. For more advanced stages of Hodgkin disease, combination chemotherapy with 3 or 4 different drugs is used.
Treatment for non-Hodgkin lymphoma depends on the grade of lymphoma (low, or high), the stage of the disease, and the age and health of the patient.
- Low-grade (slow-growing) lymphomas, the ones that occur more often in older people, may not require immediate treatment if there are no symptoms. Early, aggressive therapy does not improve survival for most low-grade lymphomas.
- Low-grade lymphoma that is advancing or causing symptoms may be treated in a variety of ways. The choice of therapy depends on the age of the person and whether there are other significant medical problems. Low dose chemotherapy won't cure the lymphoma but may help to keep decrease the number of cancer cells. More aggressive therapy would include high dose chemotherapy, sometimes with immunotherapy using a biologic agent. Also your doctors might consider a bone marrow transplant.
- For higher-grade lymphomas, the main treatment is usually high dose chemotherapy often combined with immunotherapy, with or without radiation. Your doctor may recommend a bone marrow transplant or stem cell transplant.
In a bone marrow transplant, the patient's bone marrow cells are killed and then cancer-free bone marrow cells are injected. Stem cells are immature cells that grow into blood cells. In a stem cell transplant, the patient's stem cells are removed and treated to kill the cancer before being injected back into the patient.
Immunotherapy taps the body's immune system to kill cancer cells or limit their growth. Monoclonal antibodies are the most commonly used biologic therapy to treat lymphoma. Monoclonal antibodies are very specific proteins that attack certain cells. These antibodies are made in a laboratory.
Monoclonal antibodies are injected into the bloodstream. They may be used alone or to transport drugs, toxins, or radioactive material to cancer cells.
When To Call a Professional
See your doctor if you notice swelling of one or more lymph nodes that persists for more than two weeks and/or you have other symptoms of lymphoma such as unexplained fever, weight loss and drenching night sweats.
The outlook for patients with lymphoma depends on many factors. These include:
- the type of lymphoma
- the cancer's stage
- the patient's age and general health
- whether the cancer is newly diagnosed, responds to initial treatment, or has come back.
With both types of lymphomas, it is important to be monitored throughout your life for the development of second cancers.