Special issues in pediatric Hodgkin's disease.

Childhood Hodgkin's disease (HD) is not a biologically unique disease; it differs from adult HD primarily in the relative incidence of disease histology. Preadolescent children are more likely to have Mixed Cellularity and nodular lymphocyte predominant HD. Adolescent and young adult HD is indistinguishable, with a predominance of nodular sclerosing (NS) HD. Nonetheless, treatment paradigms have diverged over the years as pediatric oncologists responded first to developmental issues in the young child, and later to the long-term treatment consequences in all young survivors. The latter concerns are of equal relevance to the young adult with HD. The increasing convergence of treatment approaches in the past decade is therefore most appropriate. Reproductive potential, risk of secondary malignancy and cardiopulmonary consequences of therapy have driven the pediatric treatment paradigm of care. Chemotherapy with low dose, limited field radiation is standard, with low-stage patients often treated by chemotherapy alone. Algorithms tailor therapy to response. The prognostic importance of very early chemotherapy response rather than end-of-chemotherapy response has led the Children's Oncology Group to use early response (after 6 wk) to titrate individual therapy and dense regimens to maximize the early response rates. Although the dose dense regimens of adult groups are similar, the pediatric algorithms emphasize using the enhanced efficacy to limit cumulative therapy. This review intends to address the special issues of childhood HD, with the intent of further encouraging understanding that will foster convergence of pediatric and adult treatment paradigms.