Non-Hodgkin's lymphoma

Overview

Lymphoma is the third most common childhood cancer. It is cancer of the lymphatic system, which is made up of thin tubes that branch like blood vessels into all parts of the body. These lymph vessels carry lymph, a colorless, watery fluid containing white blood cells called lymphocytes. Along the network of vessels are lymph nodes, groups of small bean-shaped organs that make and store infection-fighting cells.

There are clusters of lymph nodes in the underarm, groin, neck and abdomen. The lymph system also includes the spleen, the thymus, and the tonsils. Because the lymph system is so extensive, lymphoma can start in many locations and spread to almost any organ or tissue.

There are two types of lymphoma — Hodgkin's and non-Hodgkin's. The cause for both diseases is unknown and occurs in one child in 10,000.

Non-Hodgkin's lymphoma occurs between the ages of 7 and 11. It affects boys almost three times more often than girls, and is more common among Caucasian children than among African-Americans and children of other races.

Types of non-Hodgkin's lymphoma

There are three major types of childhood non-Hodgkin's lymphomas:

• Lymphoblastic — Lymphoblastic non-Hodgkin's lymphoma accounts for about 35 percent of lymphoma cases. This condition usually involves the T-cells, though it also can involve B-cells, and usually occurs with a mass in the chest and swollen lymph nodes with or without the involvement of bone marrow and the central nervous system.
• Small Noncleaved Cell — Small noncleaved cell lymphoma, also referred to as Burkitt's lymphoma, is common in Africa and North America. Burkitt's lymphoma originating in Africa is almost always associated with the Epstein-Barr virus and often occurs with a jaw mass and central nervous system disease. Burkitt's lymphoma originating in North America is rarely associated with Epstein-Barr virus, arises in the abdomen and often spreads to bone marrow.
• Large Cell or Diffuse Histiocytic — Large cell or diffuse histiocytic non-Hodgkin's involves either the B-cells or T-cells and accounts for about 15 to 20 percent of lymphoma cases. Large cell B cell lymphoma often originates in the abdomen and can spread to the bone marrow and central nervous system. Large cell T cell, also called anaplastic lymphoma, can involve the skin, lymph nodes, lungs, testicles, muscles and gastrointestinal tract.

In many children, non-Hodgkin's lymphoma is already extensive when first diagnosed. About a third of cases originate in the neck or chest, a third in the abdomen and another third elsewhere in the body.

Signs & symptoms

There is often pain and swelling at the site of the cancer. Other symptoms include:

• Abdominal bloating
• Change in bowel habits
• Fever
• Sweating, especially at night
• Weight loss

If the cancer is in the abdomen, the area can become very swollen, sometimes so much as to look like a pregnancy. When the cancer causes the lymph tissue near the kidney or intestines to swell, passage of urine or feces through that area can become blocked, causing abdominal pain.

If the chest is involved, the head and neck may swell and cause breathing difficulty. The large vein that carries blood from the head and arm back to the heart, called the superior vena cava or SVC, passes next to the thymus. Pressure on the SVC from the cancer can cause the head, arm and upper chest to turn a bluish-red color. This is known as SVC syndrome and can affect the brain and threaten your child's life. Children with SVC syndrome need immediate treatment.

Diagnosis

Many symptoms of non-Hodgkin's lymphoma could be caused by other conditions such as infections.

Your child's doctor may request a number of diagnostic tests, including:

Computed Tomography (CT or CAT) scans

This diagnostic imaging procedure provides detailed images of the body, including the bones, muscles, fat and organs.

Positron emission tomography (PET) scans

A PET scan is a nuclear medicine test in which a radioactive compound is injected and shows the areas of malignancy in the body.

Biopsy

Biopsy is the removal of a sample of tissue to see whether cancer cells are present, and it is necessary to confirm the diagnosis. There are several kinds of biopsies. Your child's doctor will choose the one best suited for your child. The goal is to get enough tissue to make an accurate diagnosis as quickly as possible with the fewest side effects.

• Fine Needle Aspiration (FNA) Biopsy — For this test, a very thin needle is used to draw a small amount of tissue from the tumor. The main advantage of FNA is that it doesn't require surgery; a drawback is that in some cases, not enough tissue can be removed.
• Excisional or Incisional Biopsy — In an excisional biopsy, the surgeon removes the entire lymph node. In an incisional biopsy, the surgeon removes a small part of a large tumor. If the node is near the skin's surface, this is a simple operation that can be done after numbing the skin. If the node is inside the chest or abdomen, your child will need general anesthesia, medicine that causes your child to sleep.
• Bone Marrow Aspiration and Biopsy — This test involves obtaining a small amount of bone marrow tissue and fluid. Usually, the sample is taken from the back of the pelvic bone. The bone is first numbed and the child also is given medicine to reduce pain or even cause sleep. A needle is put through the outer bone into the marrow and the sample is removed. This test can be used to see if cancer is present and also to help see how far the cancer has spread.
• Chest (Pleural) or Abdominal (Peritoneal) Fluid Examination — If the lymphoma has spread to the membranes that line the chest or abdominal cavities, fluid can build up. This fluid can be removed by placing a needle through the skin into the chest or abdomen. The fluid is checked to see if cancer cells are present. The skin is numbed before the test is done.

Staging

The following stages are generally used for childhood lymphomas:

• Stage I — Cancer is found in only one lymph node area or in only one area or organ outside of the lymph nodes.
• Stage II — Cancer is found in two or more lymph node areas on the same side of the diaphragm, the thin muscle under the lungs that helps with breathing, or cancer is found in only one area or organ outside the lymph nodes and in the lymph nodes around it.
• Stage III — Cancer is found in lymph node areas on both sides of the diaphragm. The cancer also may have spread to an area or organ near the lymph node or to the spleen.
• Stage IV — Cancer has spread in more than one spot to one or more organs outside of the lymph system. Cancer cells may or may not be found in the lymph nodes near these organs and may even involve lymph nodes far from the organ involved.
• Recurrent — Recurrent disease means that the cancer has come back after it has been treated. It may come back in the area where it first started or in another part of the body.

Treatment

The primary treatment for non-Hodgkin's disease is chemotherapy, which uses drugs to kill cancer cells and shrink tumors. Radiation therapy, or the use of high-dose X-rays or other high-energy rays to kill cancer cells and shrink tumors, sometimes is used. Bone marrow transplantation is being tested in studies of patients with advanced disease. The prospect for curing children is now about 70 percent overall.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells and shrink tumors. It may be taken orally or may be administered into a vein or muscle by needle. Chemotherapy is called a systemic treatment because the drugs enter the bloodstream and can kill cancer cells throughout the body. Chemotherapy also may be injected by needle into the fluid that surrounds the brain or back to treat certain types of lymphoma that spread to the brain.

Radiation Therapy

Radiation therapy, which uses X-rays at high doses in a very focused beam to kill malignant cells, is very effective in treating lymphomas. The side effects of this treatment vary depending upon which area of the body is being radiated.

Bone Marrow Transplant

Bone marrow transplant (BMT) is a newer treatment for lymphoma. Sometimes lymphoma cells become resistant to treatment with radiation therapy or chemotherapy. Very high doses of chemotherapy may then be used to treat the cancer. Because the high doses of chemotherapy can destroy bone marrow, marrow is taken from the bones before treatment. The marrow is then frozen and high-dose chemotherapy with or without radiation therapy is given to treat the cancer. The marrow that was removed is then thawed and returned by needle into a vein to replace the marrow destroyed by chemotherapy. This type of transplant is called an autologous transplant. If the marrow is from another person, the transplant is called an allogeneic transplant.