Hodgkin lymphoma in very young children: Clinical characteristics and outcome of treatment.

In developed nations, Hodgkin lymphoma (HL) is rare in <5-year olds and represent a minority in developing countries. Little is reported about the biology and behavior of these very young patients compared with older children. 18.75% of our pediatric HL patients (0 - 14 years) were <5 years at diagnosis. This group had more boys, similar incidence of B-symptoms and stage distribution, less mediastinal involvement and bulky disease, and more mixed cellularity subtype than older children. Treatment included chemotherapy (CT; n = 55), combined modality therapy (CMT; n = 12) and XRT only (n = 2). Ten-year EFS and OS was 81.5% and 90.4%, respectively, versus 75.5% and 90.5% for older children (p > 0.5). A trend toward better survival was seen with CMT, using very LD-XRT, than with CT (OS 100% vs. 86.4%[p = 0.3]; EFS 90.9% vs. 81.0%[p = 0.4]). Although CT could be effective in a subset of LR patients, LD-XRT may be needed to effectively treat most of these patients. This dose reduction may reduce XRT-related toxicity, which can be significant in very young children.