Lymphoma affects the lymphatic system, which consists of a network of lymph vessels that run throughout the body and carry lymph, a colourless, watery fluid that contains white blood cells called lymphocytes. Lymphoma results when a lymphocyte undergoes a malignant change and multiplies, eventually crowding out healthy cells and creating tumors. These tumors enlarge the lymph nodes and/or spill into other sites that are part of the immune system.
The cause of lymphoma is unknown, other than the fact that genetics is often a contributing factor. Incidence rates are higher for those who have a family member diagnosed with lymphoma, particularly a sibling. While environmental and lifestyle factors are certainly known to play a role in the development of cancer among adults, these factors have less of an impact on the development of childhood cancer.
Lymphoma accounts for one in 10 childhood cancers and is the third most common cancer in childhood. Lymphomas are divided into Hodgkin’s lymphoma and non-Hodgkin’s lymphoma. Non-Hodgkin’s is more common in young children, while Hodgkin’s lymphoma is more common in adolescents. Lymphoma is two times more common in boys than it is in girls.