Non-Hodgkin Lymphoma

Recent data from the Leukemia and Lymphoma Society report that there are currently over 628,000 people in the United States living with some form of lymphoma. This includes over 474,000 diagnoses of non-Hodgkin lymphoma, and over 153,000 diagnoses of Hodgkin lymphoma (HL).

Hodgkin lymphoma is distinguished from other diseases classified as lymphoma primarily because of the presence of Reed-Sternberg cells, which are large, cancerous cells found in Hodgkin lymphoma tissues. Non-Hodgkin lymphomas (NHL) represent a varied group of diseases distinguished by the features of the cancerous cells with each disease type.

Non-Hodgkin lymphomas can stem from B cells or T cells. They can affect multiple parts of the the lymphoid tissue, including the lymph nodes, spleen, and the bone marrow and are further classified into fast-growing or slow-growing. There have been over sixty different subtypes of NHL identified, and 6 subtypes of HL, and those numbers are increasing.

Generally, the symptoms of NHL and HL are non-specific, most commonly including shortness of breath (from lymphoma affecting the thymus or nodes around the chest), abdominal pain and swelling which can cause loss of appetite, nausea and vomiting, fatigue, fever, lymphadenopathy (swelling of the lymph nodes), drenching night sweats, intense itching of the body for unknown reason, enlargement of the spleen, and weight loss. Lymphoma in the brain can cause headaches, problems with concentration, seizures and personality changes.

The causes of most lymphomas are unknown. Most are likely caused by genetic mutations. Environmental exposure to some pesticides, chemicals and herbicides have been implicated as well. People who have autoimmune diseases, organ transplants and weakened immune systems (such as AIDS) are also at greater risk. Some viruses have been identified as causative as well, although these are regionally specific.

The cornerstone of diagnosis is pathological examination of lymphatic tissue under a microscope. A biopsy of an enlarged lymph node or bone marrow will be taken and examined to figure out the specific type of cancer based on several tissue biological markers as well as cell structure. Additionally, blood tests, CT scans of the body, and PET scans may be done to see if the cancer has metastasized.

Treatment is dependent on many factors, most importantly the type of lymphoma diagnosed, followed by the stage of the cancer, the patient's age and health status, and how symptoms have affected the body. Typically treatment involves a wide variety of chemotherapeutic agents given in specific doses and combinations for the specific lymphoma. Radiation is frequently used as well, and is usually the primary treatment for non-Hodgkin lymphoma. Additionally, many new treatments called monoclonal antibodies have been successfully used (rituximab (Rituxan) for B-cell lymphomas, ofatumumab (Arzerra) for NHL, Ocrelizumab is in clinical trials). Some patients may benefit from a bone marrow transplant.

Prognosis for the various types of lymphoma vary depending on type and stage of advancement. While each type of lymphoma has its own prognosis, it is generally a very treatable illness, with over 80% of patients diagnosed early being alive after five years. Low-grade NHL usually progresses slowly, and sometimes it takes years for the disease to progress or even need treatment. Many types of high grade disease can be completely cured with chemotherapy. Unfortunately, if chemotherapy doesn't work, the disease can spread quickly.

Doctors seldom know why one person develops non-Hodgkin lymphoma and another does not. But research shows that certain risk factors increase the chance that a person will develop this disease.

In general, the risk factors for non-Hodgkin lymphoma are mentioned below.

• Weakened immune system: The risk of developing lymphoma may be increased by having a weakened immune system (such as from an inherited condition or certain drugs used after an organ transplant).
• Certain infections:Having certain types of infections increases the risk of developing lymphoma. However, lymphoma is not contagious. You cannot catch lymphoma from another person.
• Hepatitis C virus: Some studies have found an increased risk of lymphoma in people with hepatitis C virus. More research is needed to understand the role of hepatitis C virus.
  Age: Although non-Hodgkin lymphoma can occur in young people, the chance of developing this disease goes up with age. Most people with non-Hodgkin lymphoma are older than 60. 

The following are the main types of infection that can increase the risk of lymphoma:

• Human immunodeficiency virus (HIV). HIV is the virus that causes AIDS. People who have HIV infection are at much greater risk of some types of non-Hodgkin lymphoma.
• Epstein-Barr virus (EBV). Infection with EBV has been linked to an increased risk of lymphoma. In Africa, EBV infection is linked to Burkitt lymphoma.
• Helicobacter pylori. H. pylori are bacteria that can cause stomach ulcers. They also increase a person's risk of lymphoma in the stomach lining.
• Human T cell leukemia/lymphoma virus type 1 (HTLV-1). Infection with HTLV-1 increases a person's risk of lymphoma and leukemia.
• Researchers are studying obesity and other possible risk factors for non-Hodgkin lymphoma. People who work with herbicides or certain other chemicals may be at increased risk of this disease. Researchers are also looking at a possible link between using hair dyes before 1980 and non-Hodgkin lymphoma.

Having one or more risk factors does not mean that a person will develop non-Hodgkin lymphoma. Most people who have risk factors never develop cancer.

See your doctor for painless swollen lymph nodes, drenching night sweats, unexplained fever, or weight loss that lasts. Early evaluation of persistent swelling or symptoms improves outcomes.