PURPOSE To minimize the risk of late effects in pediatric Hodgkin lymphoma (HL) by omitting radiotherapy (RT) in patients in complete remission (CR) after chemotherapy and reducing the standard radiation dose to 20 Gy in patients in incomplete remission.
Patients and methods: Between 1995 and 2001, 925 patients with classical HL (cHL) were registered from seven European countries in German Society of Pediatric Oncology and Hematology Hodgkin Lymphoma Trial 95. Patients in treatment group 1 (TG1; early stages) received two cycles of vincristine, prednisone, procarbazine, and doxorubicin or vincristine, prednisone, etoposide, and doxorubicin chemotherapy; additional two or four cycles of cyclophosphamide, vincristine, prednisone, and procarbazine were added in TG2 (intermediate stages) or TG3 (advanced stages), respectively. Patients in CR (assessed by computed tomography or magnetic resonance imaging) did not undergo RT. Those with tumor volume reduction more than 75% received reduced involved-field RT with 20 Gy and an additional 10- or 15-Gy boost only for larger residuals.
Results: Rates of overall survival, progression-free survival (PFS), and event-free survival at 10 years were (± SE) 96.3% ± 0.6%, 88.2% ± 1.1%, and 85.4% ± 1.3%, respectively. PFS for TG1 patients without or with RT was 97.0% ± 2.1% versus 92.2% ± 1.7% (P = .214) but was unsatisfactory for nonirradiated patients in TG2 (68.5% ± 7.4% v 91.4% ± 1.9%; P < .0001), with similar but not significant results in TG3 (82.6% ± 5.4% v 88.7% ± 2.0%, P = .259). Reduction of the standard radiation dose from 25 to 20 Gy did not increase failure rate.
Conclusion: RT can be omitted in early stage HL in so defined CR following this chemotherapy. RT with 20(-35) Gy proved to be sufficient in patients with incomplete remission following chemotherapy.