Updated

The American Cancer Society classifies Hodgkin disease into two types: Hodgkin disease and non-Hodgkin lymphoma.The disease is named after Thomas Hodgkin, who first described abnormalities in the lymph system. Both affect white blood cells called lymphocytes, which play a crucial role in how the immune system functions. The two types of lymphoma differ in the kind of white blood cells involved, resulting in different diagnoses and treatments. Here is a guide to understanding non-Hodgkin lymphoma:

Overview
Non-Hodgkin lymphoma is a cancer that starts in the immune system, typically attacking the lymph nodes first. The lymph nodes are the battlegrounds of the immune system, where white blood cells, or lymphocites, are stored and harmful bacteria and viruses are trapped and expelled. Non-Hodgkin lymphoma specifically affects B-cells, which protect the body against bacteria and viruses. When these B-cells reproduce at an out-of-control rate, they can build up to form a tumor. Cancerous tumors can debilitate tissue function and spread to other parts of the  body.

Symptoms and diagnosis
Non-Hodgkin lymphoma may cause swelling of the lymph nodes in the neck, armpits or groin. Additional symptoms include unexplained weight loss, abdominal pain or swelling and fatigue. This cancer may cause flu-like symptoms such as fever, soaking night sweats, coughing, difficulty breathing or chest pain. Many of these symptoms are indeterminate and often point to illnesses other than cancer. The National Cancer Institute suggests consulting a doctor if these symptoms do not go away within two weeks. If the doctor suspects non-Hodgkin lymphoma, he or she may perform a physical exam, blood test to check the number of white blood cells or x-ray to look for swollen lymph nodes. A diagnosis of cancer can only be confirmed with a biopsy — a close examination of surgically-removed tissue to look for cancer cells.

Cause
The primary cause is unknown, but there are a number of risk factors that can make one more susceptible to lymphoma. The risk factors include a weakened immune system and age, as mostly people over 60 are diagnosed with non-Hodgkin lymphoma. While lymphoma itself is not infectious, there are infectious diseases that can put one at greater risk for lymphoma. These infections include human immunodeficiency virus (HIV), Epstein-Barr, hepatitis C, HLTV-1 and hepatitis C.

Stages
The prognosis for non-Hodgkin lymphoma depends on how far the cancer has developed in the body.  Lymphoma progresses along four stages of increasing gravity. Stage I lymphoma cells appear in only one lymph node group or only one part of a tissue or organ. Stage II lymphoma has spread to at least two lymph node groups on the same side of the diaphragm or to an organ and its nearby lymph nodes. Stage III lymphoma has reached lymph nodes on both sides of the diaphragm and possibly one part of a nearby tissue or organ. Stage IV means the cells have spread throughout the body, potentially affecting the liver, blood or bone marrow in addition to the lymph nodes.

Treatment
There are various forms of treatment to combat lymphoma, and a specialist may prescribe one or a combination of therapies. Chemotherapy fights lymphoma with drugs. These drugs are taken orally, intravenously or through the spinal cord, traveling throughout the blood stream to attack the lymphoma. Biological therapy is another systemic therapy, meant to combat cancer throughout the entire body. Whereas chemotherapy fights cancer directly, biological therapy strengthens the immune system, adding armor to the body’s built-in soldiers. Radiation therapy consists of high-energy x-rays directed at the afflicted area to kill lymphoma cells. If the cancer returns, doctors may perform a stem cell transplantation. This procedure is a blood transplant with blood-forming stem cells that strengthens the patient for a high dose of radiation or chemotherapy.