BIOLOGICAL VARIABLES IN THORACIC NEUROBLASTOMA - A PEDIATRIC-ONCOLOGY-GROUP STUDY

The prognosis for patients with neuroblastoma is related to the age an d stage at time of presentation, as well as to the presence or absence of biological markers such as N-myc amplification and the degree of D NA ploidy. However, previous studies have shown that neuroblastoma in the thoracic site also is a favorable prognostic indicator, in that ch ildren with mediastinal neuroblastoma have a better survival rate, reg ardless of age or stage at time of presentation. This study was design ed to evaluate the biological differences between thoracic and nonthor acic neuroblastoma with respect to N-myc amplification, DNA index as a measure of DNA ploidy, serum lactate dehydrogenase levels, and serum ferritin lev els. Patients enrolled in the Pediatric Oncology Group st udy protocols for neuroblastoma were evaluated retrospectively, and lo g-rank analysis allowed the impact of each biological variable on surv ival to be determined for each cohort of patients. There were 1,335 ne uroblastoma patients in the data base; 227 had thoracic site neuroblas toma. Through analysis, it was apparent that patients with thoracic ne uroblastoma have better survival rates than do their nonthoracic count erparts (P < .0001), and they are less likely to have N-myc amplificat ion (P =.001), more likely to have an LDH level of less than 1,500 (P <.0001), and usually have a DNA index of greater than 1 (P <.003). Bot h thoracic and nonthoracic patients have low serum ferritin levels (86 % of thoracic versus 83% of nonthoracic patients). Thoracic-site patie nts tend to be younger than their nonthoracic counterparts (P <.0001), and they present at a lower surgicopathologic stage (P <.0001). Thora cic site was prognostically favorable for survival, when univariately stratifying for DNA index (P <.0001), lactate dehydrogenase (LDH) leve l (P <.0001), or age (P <.0001). In addition, thoracic site is associa ted with a more favorable prognosis for patients with stage C disease (P =.001), and there is a trend toward a favorable effect among stage D patients (P =.06). Patients with a thoracic site and nonamplified N- mye have a better chance of survival than do patients with nonthoracic sites who have N-mye nonamplification (P =.002); however, there were too few thoracic patients with N-mye amplification to determine its si gnificance among them (P =.40). Although patients with thoracic neurob lastoma have a favorable biological profile (N-myc nonamplified, DNA i ndex >1, LDH level <1,500, low serum ferritin level) and clinical prof ile (age <1 year, favorable stage), this may not fully explain their b etter survival rates. Copyright (C) 1995 by W.B. Saunders Company