ISHL10 Abstract T010

Long-term follow-up of contemporary treatment in early-stage favorable Hodgkin Lymphoma (HL): updated analyses of the German Hodgkin Study Group HD7 and HD10 trial

Background: Combined modality treatment (CMT) is considered as standard of care in patients with early-stage favorable HL. During the years, a gradual toxicity reduction through balancing extent and intensity of radiotherapy (RT) and chemotherapy was achieved. Long-term follow-up (FU) of the pivotal trials is needed, to ensure the applied therapies are safe and beneficial for our patients. Methods: We analyzed updated FU data of 1817 patients who were treated for early-stage favorable HL in previously published GHSG trials between 1993 and 2003. In the HD7 trial patients were randomized to either 40Gy extended-field (EF)-RT only or CMT with 2xABVD, and in HD10 to either 4x or 2xABVD and 30 or 20Gy involved-field (IF)-RT respectively. Progression-free (PFS) and overall survival (OS) were analyzed according to the Kaplan-Meier method. Cumulative incidences of secondary neoplasias (SN) were compared using Pepe & Mori’s test. The level of significance was set to 0.05. Results: The median FU was 120 and 98 months for patients in HD7 (n=627) and HD10 (n=1190), respectively. New FU data beyond the last evaluation were available for <50% of patients and last information was obtained from population registries in 18-30%. In HD7, CMT was superior to EF-RT with 15-year PFS estimates of 72.8% vs. 52.2% and a hazard ratio (HR) of 0.45 (95% confidence interval CI: 0.33-0.61). No significant differences were observed regarding OS or SN. In HD10, non-inferiority of 2xABVD + 20Gy IF-RT to more intensive treatment was confirmed with HRs of 1.0 (CI:0.6-1.5) and 0.9 (CI:0.5-1.6) and 10-year estimates of 87.2% and 94.1% for PFS and OS, respectively. No significant differences in SN were observed. Summary: Long-term FU data of HD7 and HD10 confirm the current treatment-standard in early-stage favorable HL consisting of 2xABVD + 20Gy IF-RT. In order to assess the risk of secondary neoplasia and long-term organ toxicity a prolonged follow-up period is required.