Lymphoma is the most common type of blood cancerAbnormal cell growth that cannot be controlled by the body's natural defenses. Cancerous cells can grow and eventually form tumors..  Specifically, lymphoma is a cancer that affects lymphocytesA type of white blood cell. Lymphocytes, carries along by the lymph fluid, are part of the immune system and fight infection., which are a type of white blood cell. Lymphocytes travel through the blood and lymphatic systemThe channels, tissues and organs that store and carry lymphocytes that fight infection and other diseases. to defend the body against foreign invaders like bacteria and viruses.  Lymphomas usually develop when a change, or mutation, occurs within a lymphocyte, causing the abnormal cell to replicate faster than, or live longer than, a normal lymphocyte.  Like normal lymphocytes, cancerous lymphocytes can travel through the blood and lymphatic system and spread and grow in many parts of the body, including the lymph nodesSmall bean-shaped glands located in the small vessels of the lymphatic system. There are thousands of lymph nodes located throughout the body, with clusters of them in the neck, under the arms, the chest, abdomen and groin. Lymph nodes filter lymph fluid, trapping and destroying potentially harmful bacteria and viruses., spleen, bone marrowSpongy material found inside the bones containing stem cells that develop into three types of cells: red blood cells that deliver oxygen to the body and take away carbon dioxide; white blood cells that protect the body from infection; and platelets, and other organs.

Three major categories of cancers that affect lymphocytes are:

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL): CLL/SLL are the same disease with slightly different manifestations. Where the cancerous cells gather determines whether it is called CLL or SLL. Leukemic cells develop because of a change that takes place in the cell’s DNAAbbreviation for deoxyribonucleic acid, an essential component of genes.. Approximately 19,000 people are diagnosed with CLL/SLL in the United States each year.

Hodgkin Lymphoma (HL): There are six types of HL, an uncommon form of lymphoma that involves the Reed-Sternberg cells. Approximately 9,000 people are diagnosed with HL in the United States each year.

Non-Hodgkin Lymphoma (NHL): There are more than 90 types of NHL, some of which are more common than others. Any lymphoma that does not involve Reed-Sternberg cells is classified as non-Hodgkin lymphoma. Approximately 80,000 people are diagnosed with NHL each year in the United States.

Signs and Symptoms

Certain symptoms are not specific to lymphoma and are, in fact, similar to those of many other illnesses. People often first go to the doctor because they think they have a cold, the flu or some other respiratory infection that does not go away.

Common symptoms include:

  • Swelling of lymphThe watery fluid in the lymph system that contains white blood cells (lymphocytes). nodes, which may or may not be painless
  • Fever
  • Unexplained weight loss
  • Sweating (often at night)
  • Chills
  • Lack of energy
  • Itching

Most people who have these non-specific symptoms will not have lymphoma. However, it is important that anyone with persistent symptoms be examined by a doctor to make sure lymphoma is not present.