Should adolescents with NHL be treated as old children or young adults?

The SEER (Surveillance, Epidemiology, and End Results) data for the years 1975-1998 show that children with non-Hodgkin lymphoma (NHL) have a better treatment outcome than do adults. Many factors may contribute to this age-related difference. Some factors are related to the patient (e.g., drug distribution and clearance, performance status, compliance, sex) whereas others pertain to tumor histology and biology. The spectrum of NHL subtypes is well known to differ in children and adults. From ages 5 through 14 years, Burkitt lymphoma is the predominant histologic subtype, whereas diffuse large B-cell lymphoma is most common in the 15- to 29-year age range. Because different treatment strategies are often used in children and adults with NHL, the choice of therapy for adolescents and young adults (ages 15 through 29 years) is challenging and somewhat controversial. It is reasonable to consider pediatric strategies for some adolescents and very young adults with NHL, and pediatric strategies are currently used to treat adults with certain subtypes of NHL (Burkitt lymphoma, lymphoblastic lymphoma). However, the use of pediatric strategies in adults does not guarantee a comparable outcome, as illustrated by trials for adult lymphoblastic lymphoma. There is clearly a need for further biologic study of NHL in children, adolescents, and young adults. Age-related differences in tumor biology have been demonstrated in anaplastic large-cell lymphoma (ALCL) and diffuse large B-cell lymphoma (DLBCL). Additional biologic data will not only improve prognosis and treatment stratification but, more important, will lead to the identification of specific molecular targets for therapy.