Background: The prognosis in childhood non-Hodgkin lymphoma (NHL) has improved dramatically during recent decades. The authors report the results from a 6-year population-based study of clinical characteristics and treatment results of NHL from the five Nordic countries.
Methods: All children younger than 15 years of age at diagnosis with NHL diagnosed from 1995 to 2000 were stratified and treated according to immunophenotypic classification and stage of disease.
Results: A total of 230 patients were diagnosed with primary NHL, which gives an annual incidence of 0.9/100.000 children, with a median age of 8 years. Seven percent of the children were below 3 years of age at diagnosis. The male/female ratio was 2.3 and was unrelated to age. Patients with pre-B and T-cell NHL constituted 33%, B-cell NHL 53%, and anaplastic large cell lymphoma (ALCL) 14%. According to Murphy's classification, 14% had stage 1, 17% stage 2, 50% stage 3, and 19% stage 4 disease, 12 of whom (28%) had central nervous involvement (CNS) at diagnosis. By January 1, 2003, four children had died during induction, three children died in remission (2, 6, and 26 months from diagnosis), and 24 children experienced a relapse. At 5 years, the probability of event-free survival (p-EFS) was 86+/-2% for all children. The 5-year p-EFS values for stages 1 through 4 were 94%, 97%, 83%, and 79%, respectively. The 5-year p-EFS values were 91% for B-cell, 87% for pre-B, 81% for ALCL, and 79% for T-cell NHL. The 12 patients with CNS involvement at diagnosis had a significantly poorer outcome than stage 4 patients with CNS involvement (p-EFS = 50% vs. 90%, P < 0.01). The 218 patients without CNS disease at diagnosis had a 5-year p-EFS of 88%.
Conclusions: With modern intensive chemotherapy, more than 85% of NHL patients will achieve long-lasting first remission. In the future, preventing death during induction and remission and improving therapy for patients with CNS disease would have a major impact on the overall p-EFS.