Adolescents with acute lymphoblastic leukemia: a new "age".

Adolescents with acute lymphoblastic leukemia (ALL) have a higher incidence of T-cell immunophenotype, a higher incidence of Philadelphia chromosome positive ALL, a lower incidence of high hyperdiploidy and TEL-AML1 translocation, and a lower incidence of extramedullary bulk disease compared to younger patients. There appears to be little difference between 10-15 and 16-21 year old patients. Adolescents with ALL have a lower event free survival (EFS) compared to younger patients. Adolescents 16-21 years of age treated on pediatric ALL trials have a significantly better EFS than those treated on adult trials. Pediatric treatment protocols utilize more vincristine, steroid and L-asparaginase compared to adult trials. In a recently completed Children's Cancer Group trial, adolescents 16-21 years of age had a four-year EFS of 73.1%. Avascular necrosis of bone is an important complication of therapy in adolescents with ALL.