Based on concepts of the successful German-Austrian pediatric Hodgkin studies DAL-HD 78 until-90, a new trial was initiated addressing the question whether radiotherapy can be further reduced or can be omitted in case of complete remission after initial chemotherapy, aiming at reduction of sequelae after radiotherapy, especially radiogenic second malignancies. In respect to CHEMOTHERAPY patients are stratified into 3 therapy groups (TG) according to stage and gender: 2 courses of OPPA (girls) or OEPA (boys) in TG1 (stage IA/B, IIA), and in addition 2 (TG2: stage IEA/B, IIEA, IIB, IIIA) or 4 (TG3: stage IIEB, IIIEA/B, IIIB, IVA/B) COPP courses. Boys with stage IIIB and IIIEB receive OPPA instead of OEPA. RADIOTHERAPY is administered according to response to chemotherapy independent of stage: patients with complete remission or minimal residues do not receive irradiation; patients with more than 75% tumor regression are irradiated to involved fields at a dose of 20 Gy. Doses of 30 or 35 Gy are given to regions with tumor regression below 75% or residual bulky tumor of > 50 ml, respectively. INTERIM RESULTS: From 8/95 till 1/98 we registered 385 patients under the age of 18 years from Germany, Austria, Switzerland, Sweden and the Netherlands. Therapy has been completed in 334 patients. Three patients with solitary nodular paragranuloma were treated with surgery only. Out of 331 patients 89 (26.9%) achieved a complete remission with chemotherapy. Tumor regression of more than 75% was seen in 193 (58.3%) patients and below 75% in 39 (11.8%) patients. Tumor progression during chemotherapy occurred in 1 (0.3%) patient. Response after chemotherapy was not evaluable for 9 (2.7%) patients. Radiotherapy was omitted in 91 (27.1%) patients: in TG1 50 of 142 (34%) patients, TG2 24 of 98 (24.5%) patients and TG3 18 of 94 (19.2%) patients. Initially involved regions were irradiated at a dose of 20 Gy in 164 of 334 (49.1%) patients. Doses up to 30 Gy or 35 Gy were given to 19 (5.7%) or 57 (17.1%) patients respectively. Events (tumor progression, relapse or death) occurred in 23 of 334 patients until now. The event-free survival rate is 0.91 at 2 1/2 years for all study patients and 0.89 for patients without radiotherapy. Six relapses occurred in 91 patients without radiotherapy. No relapse occurred in TG1 (n = 49), but in 5 of 24 TG2-patients, and in 1 of 18 TG3 patients without radiotherapy. As yet, the results are not significantly inferior compared with trial DAL-HD 82. Therefore this trial aiming at omitting radiation therapy in patients with complete remission after a short lasting chemotherapy will be continued. Longer follow up is necessary for final evaluations and conclusions.