Non-Hodgkin's Lymphoma

Lymphoma is a general term for cancers that develop in the lymphatic system.  Hodgkin's disease is one type of lymphoma, and all other lymphomas are grouped together and called non-Hodgkin's lymphoma.  Lymphomas account for about 5% of all cases of cancer in the U.S. In non-Hodgkin's lymphoma, cells in the lymphatic system become abnormal.  They divide and grow without any order or control, or old cells do not die as cells normally do.  Because lymphatic tissue is present in many parts of the body, non-Hodgkin's lymphoma can start almost anywhere in the body.  Non-Hodgkin's lymphoma may occur in a single lymph node, a group of lymph nodes, or in another organ.  This type of cancer can spread to almost any part of the body, including the liver, bone marrow, and spleen.

Over the years, doctors have used a variety of terms to classify the many different types of non-Hodgkin's lymphoma.  Most often, they are grouped by how the cancer cells look under a microscope and how quickly they are likely to grow and spread.  Aggressive lymphomas, also known as intermediate and high-grade lymphomas, tend to grow and spread quickly and cause severe symptoms.  Indolent lymphomas, also referred to as low-grade lymphomas, tend to grow quite slowly and cause fewer symptoms.

Incidence; Causes and Development; Contributing Risk Factors

The incidence of non-Hodgkin's lymphoma has increased dramatically over the last couple of decades.  This disease has gone from being relatively rare to being the fifth most common cancer in the United States.  At the time of writing, little is known about the reasons for this increase or about exactly what causes non-Hodgkin's lymphoma.

Doctors can seldom explain why one person gets non-Hodgkin's lymphoma and another does not.  It is clear, however, that cancer is not caused by an injury, and is not contagious; no one can "catch" non-Hodgkin's lymphoma from another person.

By studying patterns of cancer in the population, researchers have found certain risk factors that are more common in people who get non-Hodgkin's lymphoma than in those who do not.  However, most people with these risk factors do not get non-Hodgkin's lymphoma, and many who do get this disease have none of the known risk factors.

Signs and Symptoms

Symptoms of non-Hodgkin's lymphoma may also be caused by other, less serious conditions, such as the flu or other infections.

Diagnosis and Tests

If non-Hodgkin's lymphoma is suspected, a doctor asks about the patient's medical history and performs a physical exam.  The exam includes feeling to see if the lymph nodes in the neck, underarm, or groin are enlarged.  In addition to checking general signs of health, the doctor may perform blood tests.  The doctor may also order tests that produce pictures of the inside of the body, including:

• X-rays
• CT (or CAT) scan
• MRI (magnetic resonance imaging)
• Lymphangiogram: Pictures of the lymphatic system taken with X-rays after a special dye is injected to outline the lymph nodes and vessels.

A biopsy is needed to make a final diagnosis.  A biopsy for non-Hodgkin's lymphoma is usually taken from a lymph node, but other tissues may be sampled as well.  In some cases, an operation called a laparotomy may be performed.  During this operation, a surgeon cuts into the abdomen and removes samples of tissue to be checked under a microscope.

If non-Hodgkin's lymphoma is diagnosed, the doctor needs to learn the stage, or extent, of the disease.  Staging is a careful attempt to find out whether the cancer has spread and, if so, what parts of the body are affected.  Treatment decisions depend on these findings.

The doctor considers the following to determine the stage of non-Hodgkin's lymphoma:

• The number and location of affected lymph nodes
• Whether the affected lymph nodes are above, below, or on both sides of the diaphragm
• Whether the disease has spread to the bone marrow, spleen, or to organs outside the lymphatic system, such as the liver.

Treatment and Prevention

Eating well during cancer treatment means getting enough calories and protein to help prevent weight loss and regain strength.  Good nutrition often helps people feel better and have more energy.  Some people with cancer find it hard to eat a balanced diet because they may lose their appetite.  In addition, common side-effects of treatment, such as nausea, vomiting, or mouth sores, can make eating difficult.  Often, foods taste different.  Also, people being treated for cancer may not feel like eating when they are uncomfortable or tired.

Treatment for non-Hodgkin's lymphoma depends on the stage of the disease, the type of cells involved, whether they are indolent or aggressive, and the age and general health of the patient.  Non-Hodgkin's lymphoma is usually treated with chemotherapy, radiation therapy, or a combination of these treatments.  In some cases, bone marrow transplantation, biological therapies, or surgery may be options.  For indolent lymphomas, the doctor may decide to wait until the disease causes symptoms before starting treatment.  Often, this approach is called "watchful waiting".

Bone marrow transplantation (BMT) may be a treatment option, especially for patients whose non-Hodgkin's lymphoma has recurred (come back).  BMT provides the patient with healthy stem cells (very immature cells that produce blood cells) to replace cells damaged or destroyed by treatment with very high doses of chemotherapy and/or radiation therapy.  The healthy bone marrow may come from a donor, or it may be marrow that was removed from the patient, treated to destroy cancer cells, stored, and then given back to the person following the high-dose treatment.  Until the transplanted bone marrow begins to produce enough white blood cells, patients have to be carefully protected from infection.  They usually stay in the hospital for several weeks.

Patients who have a bone marrow transplant face an increased risk of infection, bleeding, and other side-effects from the large doses of chemotherapy and radiation they receive.  In addition, graft-versus-host disease (GVHD) may occur in patients who receive bone marrow from a donor.  In GVHD, the donated marrow attacks the patient's tissues (most often the liver, the skin, and the digestive tract).  GVHD can range from mild to very severe.  It can occur any time after the transplant (even years later).  Drugs may be given to reduce the risk of GVHD and to treat the problem if it occurs.

Biological therapy (also called immunotherapy) is a form of treatment that uses the body's immune system, either directly or indirectly, to fight cancer or to lessen the side effects that can be caused by some cancer treatments.  It uses materials made by the body or made in a laboratory to boost, direct, or restore the body's natural defenses against disease.  Biological therapy is sometimes also called biological response modifier therapy.

The side-effects caused by biological therapy vary with the specific type of treatment.  These treatments may cause flu-like symptoms such as chills, fever, muscle aches, weakness, loss of appetite, nausea, vomiting, and diarrhea.  Patients also may bleed or bruise easily, get a skin rash, or retain fluid.  These problems can be severe, but they usually go away after treatment stops.

Surgery may be performed to remove a tumor.  Tissue around the tumor and nearby lymph nodes may also be removed during the operation.