Purpose: To evaluate whether or not a total dose (TD) of 30 Gy is sufficient for treatment of assumed subclinical Hodgkin's Disease compared to 40 Gy TD with early stage Hodgkin's Disease (ESHD).
Methods and materials: In a prospective multicenter trial, 376 patients with laparotomy-proven ESHD stages PS IA to PS IIB without risk factors such as large mediastinum, massive splenic involvement, extranodal disease, elevated erythrocyte sedimentation rate (ESR), and/or three or more involved lymph node areas were randomly allocated either to receive (ARM A) 40 Gy TD extended field-radiotherapy (EF-RT) or (ARM B) 30 Gy TD EF-RT plus 10 Gy TD involved field-radiotherapy (IF-RT), both arms without any chemotherapy. Three hundred sixty-six of these patients were evaluable for early and long-term response, such as remission status, freedom from treatment failure (FFTF), and overall survival (OAS). For quality control, all planning and verification films as well as dose charts were prospectively reviewed by a panel of four experts, all heads of a radiotherapy department, where protocol violations (PV) were seen either with regard to errors in treatment technique, treatment volume, in TD and/or in dose/time-relationship.
Results: Treatment resulted in a complete remission (CR) of 98%; in a 5-year FFTF of 76%, and a 5-year OAS of 97%. There was no difference between the two arms in favor of 40 Gy EF compared to 30 Gy EF regarding FFTF and OAS, without any in field relapse throughout the EF volumes. Expectedly, 5-years FFTF was significantly influenced by the quality of radiotherapeutical procedures: 70% with protocol violations (PV) vs. 82% without PV.
Conclusion: Subclinical involvement in ESHD without risk factors is sufficiently treated by a TD of 30 Gy without chemotherapy, leading to a 5-years FFTF of 82% and a 5-year OAS of 97% in a multicenter treatment setting, where quality assurance is mandatory.