Recent progress in the treatment of pediatric lymphoma in Japan.

Both treatment and prognosis of pediatric non-Hodgkin lymphoma (NHL) have improved dramatically in the last 30 years. Currently, localized or limited-stage NHL (stage I to II) has an approximately 95%-100% 5-year event-free survival (EFS) rate. Furthermore, the prognosis for children with advanced-stage disease (stage III to IV) has doubled from approximately 40% 5-year EFS 30 years ago to more than 80%. Hodgkin lymphoma is also known to have around 80% 10-year EFS rate. These were accomplished not only by the advancement of chemotherapy drugs but also with the global development of organizational frameworks for pediatric clinical study. The Japanese Pediatric Leukemia Lymphoma Study Group is one of such frameworks that was organized in 2003, and it has been playing a great role in Japan ever since. In this study, I described some of the main steps of clinical studies for pediatric lymphoma according to each histologic entity. In the future, however, an effective treatment for refractory or recurrent diseases should be developed. In addition, a precise validation for low-risk patients who need reduced chemotherapy should be performed. Further clarifications on the conditions of patients with rare type lymphoma and an establishment of a standard therapy for them through a collaborative study on a global scale are needed.