Malignant lymphoma of adolescents and young adults: from the viewpoint of pediatricians.

Since adolescents and young adults (AYAs) with lymphoma began to be treated by pediatric hematologists and hematology physicians, few data have been collected regarding lymphoma in this generation of patients in Japan. We analyzed the number of pediatric hospitals that have treated hematological AYA patients. In half of the pediatric facilities, patients >15 years of age had been treated, and 40% of those facilities treated >1 AYA every year. A past lymphoma study by the Japanese Pediatric Leukemia/Lymphoma Study Group included some AYA patients. However, only the B-NHL03 study analyzed the difference between children and AYAs. In that study, 25 AYAs (7.8%) were treated among all 321 study patients. The 5-year overall survival rates of patients aged <10, 10-14, >14 years, were 88.7%, 87.0%, and 79.3%, respectively. However, this difference was not statistically significant because of the less number of patients. We analyzed data of stem cell transplantation in patients with non-Hodgkin lymphoma (NHL). Of the allogeneic transplant patients, children and AYAs did not significantly differ in treatment results. However, the 5-year transplant-related mortality after autologous transplantation was significantly higher in children than in AYAs. In NHL patients, the survival rate of AYAs after transplantation was not inferior to that of children.