Lymphoma is the third most common childhood cancer. There are 2 main types of lymphomas. The first is called Hodgkin (Hodgkins) lymphoma or Hodgkin disease. It is named after Dr. Hodgkin, who first described it in 1832. All other types of lymphoma are called non-Hodgkin lymphoma (non-Hodgkins lymphoma), or NHL. These 2 types of lymphoma are very different. They behave differently and they need different treatments. The information here covers only NHL in children.
Lymphoma is a type of cancer that starts in lymphoid tissue. Other types of cancer can start in other organs and then spread to lymphoid tissue, but these cancers are not lymphomas.
What Is Lymphoid Tissue?
Lymphoid (sometimes called lymphatic) tissue includes the lymph nodes and other organs that are part of the body's system that forms blood and protects against germs. The immune system is made up mostly of lymphoid tissue. This tissue consists of several types of cells that work together to resist infections. Lymphoid tissue is found in many places throughout the body.
The main cell type within lymphoid tissue is the lymphocyte. There are two major types of lymphocytes: B cells and T cells. These are the cells from which lymphomas develop. In fact, there are several sub-types of T cells and several stages of T-cell and B-cell development. Normal T cells and B cells do different jobs within the immune system. These differences play a part in helping doctors identify the different types of lymphomas.
Types of Lymphoid Tissue
Lymph nodes are small, bean-shaped organs found in many places throughout the body. The lymph nodes make and store white blood cells that fight infection. Lymph nodes get bigger when they fight infection, especially in infants and children.
Lymph vessels, narrow tubes something like blood vessels, connect the lymph nodes. These vessels carry a clear fluid that contains white blood cells. Other parts of the lymphatic system are described below. Lymphoid tissue is also found scattered within other organs such as the stomach and intestines.
The spleen is an organ found under the lower part of the rib cage, on the left side of the body. The spleen is the largest collection of lymph tissue in the body.
The thymus gland is an organ found in front of the heart. The thymus plays a vital role in the development of T cells, a kind of white blood cell. It becomes less active as a person gets older but it continues to function as part of the immune system.
Adenoids and tonsils are collections of lymph tissue found at the back of the throat. They are easy to see if they become enlarged during an infection or if they become cancerous.
The bone marrow (the soft, inner part of bones) makes red blood cells, clotting cells (platelets), and white blood cells. In infants, bone marrow is found in almost all bones of the body, but by the teenage years it is found mostly in the flat bones (skull, shoulder blade, ribs, hip bones) and in the back bones.
Types of Non-Hodgkin Lymphomas
Lymphomas are often divided into groups by how the cancer cells look under a microscope and their pattern of growth within the lymph node. The classification system is fairly complex. Size is described as large or small. Shape is described as cleaved (having folds) or non-cleaved. The growth pattern may be either diffuse (scattered) or follicular (in clusters of cells). Lymphomas of children are also high-grade, meaning they grow very quickly.
Nearly all non-Hodgkin lymphomas in children belong to 1 of these 3 types:
- lymphoblastic lymphoma
- small non-cleaved cell (Burkitt) lymphoma
- large cell lymphoma
The 3 types are treated very differently.
Lymphoblastic lymphomas account for just under one third of lymphomas in children. They are most common in teenagers, and boys are affected twice as often as girls. This type of lymphoma tends to spread very quickly to the bone marrow, other lymph nodes, the surface of the brain, and membranes around the heart. Because this type of lymphoma can grow so fast, it needs to be found and treated promptly.
The cancer cells of this lymphoma are the same as those in a type of leukemia. If more than one fourth of the bone marrow is involved, the disease is then called leukemia and treated as such.
Small non-cleaved cell lymphoma accounts for about half of the cases of childhood NHL in this country. It is most often seen in boys around the ages of 5 to 10. This type of lymphoma is further divided into 2 groups: Burkitt type (also called Burkitt's lymphoma) and non-Burkitt type. Children with both types have the same treatment.
In certain areas of Africa, Burkitt type is found much more often than it is here. This lymphoma is one of the fastest growing cancers known. It may spread to many organs including the surface of the brain or the inside of the brain. Because of this, it must be found and treated quickly.
Large cell lymphoma (LCL) accounts for about one fourth of all non-Hodgkin lymphoma in children. It may develop in lymphoid tissue in the neck, the area near the thymus, throat, or abdomen. Early on it may spread to the skin or tissues under the skin. Unlike the other 2 types, it seldom spreads to the bone marrow or brain. Nor does it grow as quickly as the other types.What Causes Childhood Non-Hodgkin Lymphoma?
While we do not yet know exactly what causes non-Hodgkin lymphoma, we do know that certain risk factors are linked to the disease. A risk factor is anything that increases a person's chance of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, such as smoking, can be controlled. Others, like a person's age or family history, can't be changed. But having a risk factor, or even several, doesn�t mean that a person will get the disease.
As a rule, lifestyle-related risk factors such as diet or smoking are the least important part of childhood cancer risk. Many of the risk factors for non-Hodgkin lymphoma appear to be linked to problems with the immune system. These problems may be present at birth or they may be caused by infections or drugs used to treat other diseases.
Certain genetic diseases cause some children to be born with an immune system that doesn�t work well. Because of this, these children can develop serious infections. They have an increased risk of non-Hodgkin lymphoma as well.
Children treated with radiation for some other cancers have a slightly higher risk of getting this lymphoma later in life. Patients treated with both chemotherapy and radiation are more likely to develop leukemias or non-Hodgkin lymphoma years later as a result of this treatment.
People with transplanted organs (kidney, heart, liver) are treated with drugs that weaken their immune system. This is done to keep the immune system from attacking the new organs. But at the same time, this process can increase the risk of non-Hodgkin lymphoma. The exact risk depends on which drugs were used.
Infection with the virus that causes AIDS (HIV) also weakens the immune system and is a risk factor for this cancer.
In areas of Africa where Burkitt�s lymphoma is common, chronic infection with both malaria and the Epstein-Barr virus (EBV) is an important risk factor.
It is important to remember that most children with non-Hodgkin lymphoma have no known risk factors. There is nothing these children or their parents could have done to prevent this cancer.
How Is Childhood Non-Hodgkin Lymphoma Found?
The best course of action is to pay prompt attention to any signs or symptoms of the disease. These symptoms will vary depending on the location of the tumors.
If the lymphoma is in the lymph nodes close to the surface of the body (on the sides of the neck, in the underarm area, above the collar bone, or the groin, etc.), there will be swelling in that area. Usually the child, a parent, or the doctor will notice this.
If the cancer is in the abdomen, then that area can become very swollen. When the cancer causes the lymph tissue near the kidney to swell, passage of urine through that area can become blocked, causing low urine output, tiredness, loss of appetite, nausea, or swelling in the hands or feet. The cancer may also block feces moving through the bowel. This can cause nausea, vomiting, and severe pain in the stomach area.
If the lymphoma is in the thymus or the lymph nodes inside the upper part of the chest, it can create pressure on the windpipe. This can lead to coughing, shortness of breath, or even suffocation. The large vein (called the SVC) that carries blood from the head and arm back to the heart passes next to the thymus. Pressure on this vein 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 the childs life. Children with SVC syndrome need treatment right away.
In addition to the above, non-Hodgkin lymphoma can cause other more general symptoms. These symptoms include fever, chills, or sweating, especially at night. Doctors sometimes call these effects "B symptoms."
Lymphoma in children is sometimes hard to diagnose because enlarged lymph nodes caused by infections are common. Indeed, there is usually no reason to worry unless the lymph nodes are very swollen (more than 1 inch). Even in these cases, the doctor will probably give the child 2 weeks of antibiotics before deciding on further tests. But if the lymph nodes are swelling quickly or the childs health seems to be getting worse, action is needed right away.
How Is Childhood Non-Hodgkin Lymphoma Treated?
This information represents the views of the doctors and nurses serving on the American Cancer Society's Cancer Information Database Editorial Board. These views are based on their interpretation of studies published in medical journals, as well as their own professional experience.
The treatment information in this document is not official policy of the Society and is not intended as medical advice to replace the expertise and judgment of your cancer care team. It is intended to help you and your family make informed decisions, together with your doctor.
Your doctor may have reasons for suggesting a treatment plan different from these general treatment options. Don't hesitate to ask him or her questions about your treatment options.
Before treatment starts, it�s a good idea to talk to the cancer care team about the side effects your child might have. They can tell you about the common side effects, how long they might last, and how serious they might be.
Even if the disease appears to be confined to a single lymph node, it is likely to have spread already. There may be cancer cells in other organs, but these are too small to be felt or seen on imaging tests. This is why surgery and radiation are not commonly used to treat this disease, except to get a better biopsy sample or to relieve a blockage in the child�s intestine.
Radiation can also be used to ease symptoms such as pain caused by the disease. Side effects of radiation treatment can include mild skin problems or tiredness. Treatment to the abdomen can cause upset stomach and diarrhea. Often these effects go away after a short while.
But there can be long-term side effects. Radiation to the chest may cause lung damage and lead to breathing problems. There can also be a higher risk of getting lung cancer or breast cancer (for girls) in later years. If the brain received radiation treatment, side effects such as headaches and trouble thinking could show up 1 or 2 years later. Treatment to the chest could affect the heart and blood vessels. And there is the danger of other cancers (sarcomas) developing later.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. Usually the drugs are given into a vein or by mouth. Once the drugs enter the bloodstream they spread throughout the body. This treatment is useful for cancer that has spread to other organs. For non-Hodgkin lymphoma, a combination of several drugs is given over a period of time. All 3 types of this disease are treated with chemotherapy. The difference is in which drugs are used and for how long they are given.
Chemotherapy can have some side effects. These side effects depend on the type of drugs given, the amount given, and how long treatment lasts. Side effects could include the following:
- hair loss (the hair grows back after treatment ends)
- diarrhea
- nausea
- mouth sores
- increased chance of infection (from low white blood cell counts)
- bleeding or bruising after minor cuts or injuries (from a shortage of platelets, cells that help the blood form a clot)
- fatigue (from low red blood cell counts)
Your child's doctor can often suggest ways to reduce these side effects. Drugs can be given along with chemotherapy to prevent or reduce nausea and vomiting. Drugs known as growth factors can be given to help keep the blood cell counts higher.
Tumor lysis syndrome is a side effect of chemotherapy that results from the rapid breakdown of lymphoma cells. When the cells are destroyed, they release their contents into the bloodstream. This can affect the kidneys, heart, and nervous system. The problem can be prevented by making sure the child gets lots of fluids and giving certain drugs that help the body get rid of these substances.
Organs that can be directly damaged by some chemotherapy include the kidneys, liver, testes, ovaries, brain, heart, and lungs. With careful watching, life-threatening side effects are rare. Sometimes the chemotherapy may have to be reduced or stopped for a while.
One of the most serious side effects of treatment is the possibility of your child getting a second cancer called AML (acute myeloid leukemia). This is quite rare, and the importance of chemotherapy in treating non-Hodgkin lymphoma in children far outweighs the small risk.
Monoclonal antibodies are another form of treatment. They are like antibodies that are made by the immune system, but they are made in the lab. Instead of attacking germs the way natural antibodies do, some monoclonal antibodies are designed to attack lymphoma cells.
After years of research, several monoclonal antibodies are now being used as treatments for lymphoma. In fact, more monoclonal antibodies are available to treat lymphoma than any other type of cancer.
The first monoclonal antibody approved by the FDA to treat any cancer was rituximab (Rituxan). Common side effects are usually mild but may include chills, fever, nausea, rashes, fatigue, and headaches. Even if these problems happen when rituximab is first given, it is very unusual for them to continue. Other monoclonal antibodies to treat lymphomas are also being developed.
Bone Marrow Transplantation (BMT) and Peripheral Stem Cell Transplantation (PBSCT)These treatments are used for children who relapse during or after treatment. They allow doctors to use higher doses of chemotherapy than would normally be the case. But high doses of chemotherapy drugs destroy the bone marrow, which prevents new blood cells from being formed. This could be life-threatening.
Doctors try to avoid this problem by giving the child blood-forming stem cells after treatment. The stem cells are able to create new bone marrow cells. These stem cells can be taken either from the child and stored before treatment, or they can be donated from another person.
In the first approach (called an autologous transplant), the stem cells are removed from the child�s bone marrow or bloodstream before treatment starts. They are frozen and stored. After treatment with high doses of chemotherapy (and sometimes radiation), the cells are thawed and returned to the child through a vein. This is the most common approach.
The second method (called an allogeneic transplant) uses cells from another person. This may be done when cancer cells are found in the child�s own bone marrow in order to avoid returning cancer cells to the child after treatment.
If the child has a brother or sister who has the same tissue type, their bone marrow cells (or perhaps stem cells from the blood) can be used instead of the child�s own cells. If a parent is a close match to the child, the parent's cells can be used. A matched, unrelated donor might also be used.
These transplant treatments are complex. If the doctor thinks your child might benefit from transplantation, the best place to have it may be in a nationally recognized cancer center or in a hospital associated with a university. The staff there should have experience with the procedure. To learn more about this treatment, please see the ACS document, Bone Marrow and Peripheral Blood Stem Cell Transplants.
Childhood Non-Hodgkin Lymphoma Survival Rates
The five-year survival rate for children younger than 20 years old with non-Hodgkin lymphoma ranges from around 70% to 90%, depending on the exact type of lymphoma. This rate refers to patients who live at least 5 years after the cancer is found. Of course, many patients live much longer than 5 years.
These numbers provide an overall picture, but keep in mind that every persons situation is unique and the numbers can't predict exactly what will happen in your childs case. Talk with your cancer care team if you have questions about your childs chances of a cure. They know your child's situation best.
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