From involved- field to involved-node – Quality analysis of the radiation therapy in HD 17 by the expert panel of the German Hodgkin Study Group
The use of radiotherapy (RT) for intermediate-stage Hodgkin lymphoma is discussed vividly. The HD17 trial of the German Hodgkin Study Group (GHSG) evaluated the value of consolidative involved-node (IN)RT for patients with PET-positivity after chemotherapy and enabled a comparison between INRT and involved-field (IF)RT . The present work analyzes the quality of the performed RT.
For quality assessment, all INRT-plans in the HD 17 trial were requested and compared to a random selection of IFRT-cases in the standard arm. The RT was assessed by experts of the radiation therapy panel of the GHSG using initial (staging) imaging, RT plans and the recommendation forms by the reference radiation oncology. Evaluation was graded as „correct“, „minor deviation“ or „major deviation“. Statistical analyses were per-formed using a chi-square test in SPSS (version 27/28, IBM, NY, USA).
In total, 178 patients (INRT: 136, IFRT: 42) were analyzed, treated with a median RT dose of 30 Gy (IFRT: 18-30.6 Gy, INRT: 14 Gy-40 Gy). The majority (76.5 %) of INRT-cases showed no deviation compared to 69.1 % of IFRT-cases. Deviations were reported for 9.6 % and 14.0 % of patients in the INRT-group compared to 11.9 % and 19.1 % in the IFRT-group for minor and major deviations, respectively. There was no significant difference between both cohorts regarding the percentage of plans with deviations (p=0.333) or the percentage of major deviations (p=0.423). The principal causes for major deviations were too narrow target volumens in the involved region (IFRT: 6 vs. INRT: 1) or incorrect RT doses (IFRT: 1, INRT: 2).
The performed INRT was delineated and planned correctly in most cases and reveals a high degree of quality. There has been no decline in RT-planning in comparison to IFRT. Continuous education is pivotal to enable high-quality INRT outside of clinical trials.
1 Lancet Oncol. 2021 Feb;22(2):223-234.