ABSTRACT
Prognostic significance of residual mediastinal tumor mass in children treated for HD as well as the choice of the optimal management of these cases still remains unknown. In years 1994-2001 in 10 PPLLSG participating centers 480 children (age 2-19.7 years) were treated for HD (stages I-IV). In 338 cases initial mediastinal/lung hilus involvement was present. All patients with initial mediastinal/lung hilus involvement were treated with multidrug chemotherapy combined with involved field radiotherapy. In five cases remission was not achieved. Complete remission (CR) was achieved in 226 patients and uncertain complete remission (UCR) in 107 patients, in whom after completion of planned treatment residual changes in mediastinum/lung hilus were identified in radiological examinations. Twenty four children with persistent mediastinal tumor underwent thoracoscopy or thoracotomy. In only one case histopathological examination revealed the presence of neoplastic cells in mediastinal mass tissue, in 2 another cases cystic changes in mediastinum were present, in one case thymic tissue was identified, necrotic tissue was present in 20 cases. Among 107 children with residual mediastinal tumor and 226 patients with CR achieved, relapses occurred in 6 and 18 patients respectively. Over 5-year relapse-free survival was 92.4% and 91.3% respectively. Patients with the presence of mediastinal/lung hilus tumor after the completion of the treatment do not have an increased risk of relapse, but before the completion of therapy they require careful, clear-sighted and repeated examinations including computed tomography (CT), magnetic resonance imaging (MRI) and especially positron emission tomography (PET) to evaluate the nature of persistent lesions. Only in clinically and radiologically doubtful cases tumor biopsy with subsequent histopatological examination should be performed.
