Preliminary results of the multicenter trial GPOH-HD 95 for the treatment of Hodgkin's disease in children and adolescents: analysis and outlook.

Background: In 5 consecutive pediatric and adolescent Hodgkin's disease trials DAL-HD since 1978 the invasive diagnostic procedures and the radiotherapy have gradually been reduced and chemotherapy modified to minimize toxicity and the risk of late effects. Since 1982 the overall survival increased up to 95%. In this trial the possibility of reducing local radiation doses to 20 Gy in patients with good response to chemotherapy and omitting radiotherapy totally for patients with complete remission after chemotherapy was tested.

Patients and Methods: Over a period of 6 years, from August 1995 to July 2001, 1018 children and adolescents with Hodgkin's disease from Germany, Austria,Switzerland, the Netherlands, Sweden, Norway and Denmark were enrolled in this trial. The chemotherapy was equivalent to previous trial DAL-HD 90. The treatment group (TG) 1 (stages I and IIA) received 2 cycles OPPA for girls and 2 cycles OEPA for boys, TG2 (stages IIEA, IIB, IIIA) and TG3 (stages IIEB, IIIEA, IIIB, IV) received additional 2 or 4 cycles COPP respectively. In contrast to trial DAL-HD 90 boys in stage IIIB and IIIEB received OPPA instead of OEPA. The initial staging as well as the restaging for evaluating tumor volume reduction after chemotherapy was reviewed by the study center. Radiotherapy was planned accordingly: patients with complete remission after chemotherapy were not irradiated (21.9%); all other patients received local radiotherapy to the initially involved sites, depending on the tu-mor response. Patients with a partial remission of> 75 tumor regression were irradiated with 20 Gy (50AX), partial remission of< 75% with 30 Gy (4.1 %), and residual masses of > 50 ml were boosted up to 35 Gy (20.2 %).

Results: 36 tumor progressions and 49 relapses occurred over a period of 7 1/2 years (median followup 3 years, data deadline 12/19/02). Kaplan-Meier-analysis after 5 years showed a probability for event-free survival (pEFS) for all patients of 0.88 and for overall survival (pOS) of 0.97. For the total group the pDFS (disease free survival) was lower in 222 non irradiated patients than in the 758 irradiated patients (0.88 vs. 0.92,p - 0.049). But there was a difference between the individual treatment groups. In TG 1 there was no difference between nonirradiated and irradiated patients (0.97 vs. 0.94) and the non-ir-radiated patients showed a better trend. In TG 2, and in TG 2 and TG 3 combined, the pDFS was significantly worse for non irradiated patients in comparison with the irradiated patients (TG2:0.78 vs. 0.92; TG 2 +3:0.79 vs. 0.91). Compared to former DAL-HD trials the pOS stayed stable despite therapy reduction.

Conclusions: A reduction of radiotherapy to 20 Gy for patients in all stages with good response to chemotherapy is possible without deterioration of the results. The omission of radiotherapy for patients in complete remission after chemotherapy is recommended only for patients in early stages (TG1). In future trials the possibility of a wider selection for chemotherapy alone for this group needs to be evaluated. In intermediate (TG2) and advanced (TG3) stages omission of radiotherapy for patients incomplete remission results in a lower pEFS, but the pOS is not significantly reduced. Only with knowledge of the long term effects of today's therapy we can give a satisfactory answer to the question whether in future trials the primary aim should be pEFS as high as possible due to front-line-therapy or reduction of late effects.