Burkitt lymphoma is a form of non-Hodgkin's lymphoma in which cancer starts in immune cells called B-cells. Recognized as the fastest growing human tumor, Burkitt lymphoma is associated with impaired immunity and is rapidly fatal if left untreated. However, intensive chemotherapy can achieve long-term survival in more than half the people with Burkitt lymphoma.
Burkitt lymphoma is named after British surgeon Denis Burkitt, who first identified this unusual disease in 1956 among children in Africa. In Africa, Burkitt lymphoma is common in young children who also have malaria and Epstein-Barr, the virus that causes infectious mononucleosis. One mechanism may be that malaria weakens the immune system's response to Epstein-Barr, allowing it to change infected B-cells into cancerous cells. About 98% of African cases are associated with Epstein-Barr infection.
Outside of Africa, Burkitt lymphoma is rare. In the U.S., about 1,200 people are diagnosed each year, and about 59% of patients are over age 40. Burkitt lymphoma is especially likely to develop in people infected with HIV, the virus that causes AIDS. Before highly active antiretroviral therapy (HAART) became a widespread treatment for HIV/AIDS, the incidence of Burkitt lymphoma was estimated to be 1,000 times higher in HIV-positive people than in the general population.
Types of Burkitt Lymphoma
In the World Health Organization classification, there are three types of Burkitt lymphoma:
- Endemic (African). Endemic Burkitt lymphoma primarily affects African children ages 4 to 7 and is twice as common in boys.
- Sporadic (non-African). Sporadic Burkitt lymphoma occurs worldwide. Globally, it accounts for 1% to 2% of adult lymphoma cases. In the U.S. and Western Europe, it accounts for up to 40% of pediatric lymphoma cases.
- Immunodeficiency-associated. This variant of Burkitt lymphoma is most common in people with HIV/AIDS. It accounts for 30% to 40% of non-Hodgkin lymphoma in HIV patients and may be an AIDS-defining disease. It also can occur in people with congenital conditions that cause immune deficiency and in organ transplant patients who take immunosuppressive drugs.
Compared to the endemic type, the incidence of Epstein-Barr infection is considerably lower in the other two types of Burkitt lymphoma. In the sporadic disease, Epstein-Barr occurs in about 20% of the patients. With the immunodeficiency-associated type, it occurs in about 30% to 40% of patients. So, the association of Epstein-Barr with these two types of Burkitt lymphoma is unclear.
Symptoms of Burkitt Lymphoma
The symptoms of Burkitt lymphoma depend on the type. The endemic (African) variant usually starts as tumors of the jaw or other facial bones. It also can affect the gastrointestinal tract, ovaries, and breasts and can spread to the central nervous system, causing nerve damage, weakness, and paralysis.
The types more commonly seen in the U.S. -- sporadic and immunodeficiency-associated -- usually start in the bowel and form a bulky tumor mass in the abdomen, often with massive involvement of the liver, spleen, and bone marrow. These variants also can start in the ovaries, testes, or other organs, and spread to the brain and spinal fluid.
Other symptoms associated with Burkitt lymphoma include:
Diagnosis of Burkitt Lymphoma
Because Burkitt lymphoma spreads so quickly, prompt diagnosis is essential.
If Burkitt lymphoma is suspected, all or part of an enlarged lymph node or other suspicious disease site will be biopsied. In a biopsy, a sample of tissue is examined under a microscope. This will confirm or rule out Burkitt lymphoma.
Additional tests may include:
- Computed tomographic (CT) imaging of the chest, abdomen, and pelvis
- Chest X-ray
- PET or gallium scan
- Bone marrow biopsy
- Exam of spinal fluid
- Blood tests to measure kidney and liver function
- Testing for HIV disease
Treatments for Burkitt Lymphoma
Intensive intravenous chemotherapy -- which usually involves a hospital stay -- is the preferred treatment for Burkitt lymphoma. Because Burkitt lymphoma can spread to the fluid surrounding the brain and spinal cord, chemotherapy drugs also may be injected directly into the cerebrospinal fluid, a treatment known as intrathecal chemotherapy.
Examples of drugs that may be used in various combinations for Burkitt lymphoma include:
- cyclophosphamide (Cytoxan)
- cytarabine (Cytosar-U, Tarabine PFS)
- doxorubicin (Adriamycin)
- etoposide (Etopophos, Toposar, VePesid)
- methotrexate (Rheumatrex)
- vincristine (Oncovin)
Other treatments for Burkitt lymphoma may include intensive chemotherapy in combination with:
- Rituximab (Rituxan), a monoclonal antibody that sticks to proteins on cancer cells and stimulates the immune system to attack cancer cells
- Autologous stem cell transplantation, in which the patient's stem cells are removed, stored, and returned to the body
- Radiation therapy
- Steroid therapy
In some cases, surgery may be needed to remove parts of the intestine that are blocked, bleeding, or have ruptured.
Prognosis for Burkitt Lymphoma
Burkitt lymphoma is fatal if left untreated. In children, prompt intensive chemotherapy usually cures Burkitt lymphoma, leading to long-term survival rates of 60% to 90%. In adult patients, results are more variable. Overall, prompt treatment is associated with long-term survival rates of 70% to 80%.