Lymphoma is the name of a group of blood cancers that arise in the lymphatic system, which is one part of the immune system, the body’s natural defense against infection. The lymphatic system is made up of a network of vessels that carry a fluid called lymph throughout the body. Lymph contains lymphocytes (a type of white blood cell) that attack infectious agents. These lymphocytes circulate throughout the body through the bloodstream and lymphatic system.
Lymphoma occurs when normal lymphocytes are transformed into abnormal, cancerous lymphocytes that reproduce uncontrollably. As they multiply, they collect in one or more lymph nodes or other parts of the body, including bone marrow, the spleen, tonsils, adenoids and other organs, where they can form tumors. These cells begin to outnumber normal cells, causing enlargement of the lymph nodes, spleen and other organs.
Lymphoma is the most common blood cancer in the United States and represents 67 different cancer subtypes that involve lymphocytes. The body has two main types of lymphocytes that can develop into lymphomas: B-lymphocytes (B-cells) and T-lymphocytes (T-cells). B-cells produce antibodies, which are proteins that attach to infectious organisms, such as bacteria and viruses. T-cells attack infectious agents directly and play a part in controlling the immune system.
Lymphoma can occur in adults and children of any age. The two main forms of lymphoma are non-Hodgkin lymphoma and Hodgkin lymphoma. Hodgkin lymphoma occurs most frequently in adolescents and young adults ages 15 to 40 and in people older than 55. Non-Hodgkin lymphoma more often occurs in older adults, with most cases occurring in people age 60 or older.
Risk factors for lymphoma
No one knows exactly what causes lymphoma, but mutations in DNA, the hereditary genetic material found in cells, leads to the development of the disease. What triggers these mutations, however, is largely unknown, but research suggests that certain risk factors may play a role, including:
Exposure to a number of chemicals, including highly toxic chemical solvents such as benzene, toluene, turpentine and xylene
Exposure to radiation from atomic bombs and nuclear reactor accidents
Exposure to chemical herbicides and pesticides used for pest control and defoliation (including Agent Orange, used as a defoliant in the Vietnam War)
Exposure to hair dyes, particularly those made before 1980
Inherited immune disorders, such as rheumatoid arthritis, lupus, Sjögren’s syndrome and celiac disease
Immune system disorders, such as HIV infection and AIDS
Certain infections, such as the Epstein-Barr virus (which causes mononucleosis) and Helicobacter pylori infection (a bacterial infection that can cause ulcers)
Symptoms and early diagnosis
Early diagnosis and treatment of lymphoma is important. Swollen lymph nodes in the neck, armpits, chest, abdomen or skin are among the major symptoms of lymphoma, but swollen nodes in the neck may also indicate the flu or a sinus infection. Swollen nodes in the chest may cause trouble breathing, and tumors in the skin may appear as itchy red or purple lumps. In people with sinus infections, swollen nodes are generally tender and often hurt to some degree; however, in people with lymphoma, swollen lymph nodes might be firm and painless.
Those with lymphoma may also have chest pain when the disease spreads to the upper chest just behind the breastbone. Unexplained weight loss of 10 percent or more of body weight is another possible symptom, as are recurring fevers and night sweats that develop for no apparent reason, especially with other symptoms.
Other symptoms include rashes, itchy skin and lesions, which might be signs of skin lymphoma, and lower back pain in the presence of other symptoms. Lymph nodes may also be painful after drinking alcohol because it puts stress on the lymphatic system.
If you have any of these symptoms, see your physician and explain your concerns about lymphoma. To diagnose this disease, your doctor will take a medical history and perform a physical exam. If your doctor suspects lymphoma, he or she will remove a small piece of a node or an entire node for examination under a microscope (biopsy).