SHOULD NASAL-PARANASAL-ORONASOPHARYNGEAL LYMPHOMAS IN CHILDREN BE CLASSIFIED DIFFERENTLY FROM THE OTHER LOCALIZATIONS?

Since 1975, improvements in chemotherapy and dose intensi® cation have transformed the outcome in non-Hodgkin lymphoma (NHL). Childhood NHL differs from adults in that it usually behaves aggressively, both clinically and histologically, and often presents at an extranodal location. The Children’s Cancer Group (CCG) study (CCG-551) [1] has shown that treatment should be adapted according to immunology. Moreover, high-dose methotrexate in combination with systemic treatment increases the outcome and decreases the incidence of central nervous system (CNS) relapse [2]. In a previous issue of Pediatric Hematology and Oncology [3], Yaris et al. report retrospectively their experience in treating 55 children with nasal ± paranasal ± oronasopharyngeal (NPONP) NHL. The study period was 23years, and 7 different regimens were used to treat these patients. We agree with the authors that intrathecal treatment and doxorubicin are important components in lymphoma treatment and that early stage disease (I or II), whatever the system classi® cation, requires aggressive chemotherapy. The most important prognostic factor in NHL is the treatment received. The authors have also compared the St. Jude classi® cation [4] and the TNM staging system [5] and conclude that the TNM system is more accurate for NPONP lymphomas in children. We are not convinced by this conclusion. The aim of staging and subsequent classi® cation is (1) to de® ne the exact disease extent, (2) to adapt the treatment accordingly, (3) to de® ne subgroups according to prognostic factors, and (4) to compare international patient populations. All classi® cation systems share simplicity and each has its own individual problems. In particular, in childhood lymphomas, not only the extent of the disease but also the cellular characteristics (T or B cell) have to be considered. The following questions would be answered.