In a national multicenter trial in the Federal Republic of Germany, patients with Hodgkin's lymphoma in stages I, II and IIIA presenting with large mediastinal tumor (MT), extranodal (E), or massive spleen (S) involvement received a combined modality treatment with 2x (COPP + ABVD) followed by 20 or 40 Gy EF radiation (HD1 protocol). By October 1987, 89 patients aged 15-60 years had finished therapy and were evaluable for response. Of these 74 (83%) achieved complete remission (CR). After 3 years freedom from treatment failure (FFTF) is 80% (+/- 8%, 95% confidence interval) and survival (SV) 92% (+/- 6%, 95% confidence interval). In a univariate and multivariate analysis using FFTF as endpoint we could not identify any particularly prominent prognostic risk factor among the following examined: stage, constitutional symptoms, MT, E stage, S involvement, age, sex, histology, laparotomy, erythrocyte sedimentation rate (ESR), leukocytes, lymphocytes, and alkaline phosphatase (AP). These data suggest that the inclusion criteria have selected a fairly homogeneous group of patients with respect to prognosis. In a separate trial (HD3 protocol) patients in stages IIIB/IV received induction chemotherapy with 3x (COPP + ABVD). Patients in complete remission (CR) received consolidation therapy by either radiotherapy (20 Gy IF) or further chemotherapy (COPP + ABVD). Patients not in CR received salvage therapy (40Gy in the case of persisting nodal disease, or else 4x CEVD chemotherapy). By October 1987, 137 patients had finished therapy and were evaluable for response. Of these 86 (63%) achieved CR after induction chemotherapy. Including salvage therapy a total of 104 patients (76%) achieved CR. After 3 years FFTF is 56% (+/- 10%, 95% confidence interval) and SV 84% (+/- 8%, 95% confidence interval). Univariate and multivariate prognostic risk factor analyses were performed using FFTF as endpoint. Sex, age, stage, splenectomy, bone marrow, and liver and bone involvement had no prognostic impact. In contrast, a pretreatment erythrocyte sedimentation rate (ESR) above 80 mm/h and a serum alkaline phosphatase (AP) above 230 IU/ml each appeared as significant prognostic factors (P less than 0.01; relative risk, 2.3). The two parameters can be combined to separate two groups (A: ESR and AP both low; B: ESR and/or AP high) which differ significantly for FFTF (P less than 0.001) and survival (P less than 0.04). The decision for risk-adapted treatment requires identification of groups of patients in the frame of specified diagnostic and therapeutic strategies.(ABSTRACT TRUNCATED AT 400 WORDS)