The blood contains red cells that carry oxygen, platelets that stop bleeding and white cells that fight off infection. Lymphomas are a cancer of a particular type of white blood cell called a lymphocyte. Two major types of lymphomas exist: Hodgkin's lymphoma and non-Hodgkin's lymphoma, or NHL.
Pathology
Like all cancers, NHL is a disordered, unchecked overgrowth of cells. Mutations in genes that cause overgrowth or protect against normal programmed cell death can lead to cancer. The DNA encoding the cell's genes is stored in 46 chromosomes. Various mutations of the DNA or rearrangement of chromosomes may lead to cancer. There also may be insertion of genes for cell growth from a virus.
Risk Factors
According to the American Cancer Society, risk factors for NHL include immune disorders, which can be present at birth, such as HIV, or acquired. Other risk factors include immune system disorders such as rheumatoid arthritis or lupus, as well as certain chemicals and drugs, and infectious disease such as the virus HTLV-1.
Symptoms
NHL may be slow growing over several years time, or act very aggressively. Aggressive lymphomas may present with a rapidly growing mass, fever, weight loss and night sweats. Less aggressive lymphomas may present with slowly growing lymph nodes, or an enlarging liver or spleen. Less common presentations include rashes, fatigue, fever, fluid in the chest or abdomen. Emergencies may include compression of the spinal cord, heart, major blood vessels or airways, severe liver failure, or drop in blood counts.
Diagnosis
Along with the history of the aforementioned symptoms, certain physical exam, laboratory, and imaging results aid in the diagnosis. Physical exam findings include swollen lymph nodes, liver and spleen. Laboratory results may include an elevated enzymes or chemicals in the blood, and blood counts that are too high or too low. Imaging of the chest by x-ray may show swollen lymph nodes, particularly behind the sternum. Diagnosis is best made with a biopsy of lymph nodes or other affected organs to study the tissue under a microscope.
Staging and Prognosis
Imaging, such as CT scans, may be used to evaluate the extent of disease. The Ann-Arbor system for staging lists four stages. Stage I refers to involvement in a single lymph node region or site. Stage IV is diffuse involvement of organs such as the lungs, liver or bone marrow. Stages II, III and IV are between these two extremes. The most common tool used to come up with a prognosis is called the "international prognostic index." Some of the factors determining prognosis include age of the patient, general health, lab values, Ann-Arbor stage and number of organs involved.
Treatment
Treatment of NHL is highly variable. A localized lymph node may be treated with radiation. The drug, rituximab is sometimes an option, with or without standard chemotherapy. There are multiple chemotherapy regiments available, such as CHOP, which includes the drugs cyclophosphamide, doxorubicin, vincristine and prednisone. Surgery to transplant healthy cells that can divide and make more healthy cells may also be an option.
