What Causes Non-Hodgkin Lymphoma in Children?
Currently, scientists do not know what causes non-Hodgkin lymphoma in children. Non-Hodgkin lymphoma is a type of cancer associated with the immune system because it begins in a type of white blood cell called a lymphocyte. Normally, lymphocytes, like other healthy cells, grow, replicate, and then die. For some reason, DNA changes within certain lymphocytes cause them to grow into cancerous cells, which then divide into more cancerous cells. Why these DNA changes lead to this change is unknown, however.
Because non-Hodgkin lymphoma is associated with the immune system, there is a link between the development of NHL in some children and a compromised immune system such as associated with Epstein-Barr Virus or HIV infection. EBV, for instance, infects B lymphocytes, potentially causing them to have an increased risk of gene changes associated with NHL. However, it is important to note that the vast majority of children here in the United States who are diagnosed with NHL do not have EPV or a compromised immune system. What causes NHL in these children is unknown.
What are the Risk Factors for Non-Hodgkin Lymphoma?
A “risk factor” is anything that may impact a child’s changes of developing cancer. For example, in adults, risk factors for cancer sometimes include lifestyle choices such as smoking and tobacco use. For children, however, lifestyle choices are not believed to be linked to the development of cancer, so if there are any known risk factors for childhood cancers, they are usually genetic or otherwise immutable.
The most common risk factors for non-Hodgkin lymphoma include:
Age, gender, and race: although scientists to do not understand why, NHL is more common in older children than younger children. It is more common in boys than girls and more common in white children than black children.
Weakened immune system: a compromised immune system has been linked with a higher risk of developing childhood NHL. The immune system may be compromised due to: an underlying genetic condition (such as severe combined immunodeficiency syndrome (SCID), common variable immunodeficiency, Ataxia-telangiectasia, or X-linked lymphoproliferative syndrome); an organ transplant involving immuno-suppressive drugs required to prevent organ rejection; and/or HIV/AIDS.
Radiation exposure: High levels of radiation exposure—such as survivors of atomic bombs or nuclear reactor accidents—have an elevated risk of developing some types of cancers, including NHL. Lower levels of radiation such as from x-rays are not known to be linked to the development of NHL; however, physicians generally try to avoid any unnecessary radiation exposure for pregnant women and infants/young children just in case. Radiation treatment for other cancers also involves an elevated risk of NHL and other second cancers; however, in these cases, NHL usually develops later in life as adult NHL.
Epstein-Barr Virus (EBV): While the linkages are not well understood, individuals with Epstein-Barr Virus have a higher risk of developing NHL. This is especially true in Africa where EBV has been linked to almost 90% of Burkitt lymphoma diagnoses. It has been linked with about 15% of Burkitt lymphoma here in the United States and is also linked to post-organ transplant lymphomas.
Can Non-Hodgkin Lymphoma Be Prevented?
There is a simple answer to this critical question: no. Most children diagnosed with non-Hodgkin lymphoma have no risk factors or lifestyle issues that could have been altered or changed in any way to prevent the development of this disease. While it is entirely natural and very common to search for a cause or something to blame when a child is diagnosed with NHL (or any type of cancer), it is important that parents and guardians understand that there is nothing that they could have done differently to prevent this disease.
There are two notable exceptions. First, a small percentage of diagnoses are associated with a compromised immune system such as HIV infection. HIV-positive mothers are encouraged to take active steps during and after pregnancy to reduce the risk of passing HIV along to their children. Second, NHL may develop as a second cancer stemming from a prior cancer treatment or immune-suppressing drugs taken to facilitate an organ transplant. Obviously, in these cases, the small risk of developing NHL in the future must be weighed against the need to treat a potentially life-threatening disease in the present.
About American Childhood Cancer Organization
American Childhood Cancer Organization (ACCO) is a non-profit charity dedicated to helping kids with cancer and their families navigate the difficult journey from cancer diagnosis through survivorship. Internationally, ACCO is the sole U.S. member of Childhood Cancer International (CCI), the largest patient-support organization for childhood cancer in the world. Here in the United States, ACCO promotes the critical importance of ensuring continued funding into new and better treatment protocols for childhood cancer. And most importantly, ACCO is focused on the children: developing and providing educational tools for children fighting cancer and their families, empowering them in their understanding of childhood cancer and the medical decisions they must make during this difficult journey. All of ACCO’s resources are available free of charge for families coping with childhood cancer.
For additional information about childhood cancer or on ACCO, or to order resources for you or your child, please visit our website at www.acco.org.