Interobserver delineation uncertainty in involved-node radiation therapy (INRT) for early-stage Hodgkin lymphoma: on behalf of the Radiotherapy Committee of the EORTC lymphoma group

Authors

  • Marianne C. Aznar Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  • Theodore Girinsky Service de Radiothérapie Oncologique, Institut Gustave Roussy, Villejuif, France
  • Anne Kiil Berthelsen Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  • Berthe Aleman Department of Radiotherapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands
  • Max Beijert Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
  • Martin Hutchings Department of Haematology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  • Yolande Lievens Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium
  • Paul Meijnders Department of Radiation Oncology GZA, Iridium Cancer Network, University of Antwerp, Antwerp, Belgium
  • Peter Meidahl Petersen Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; ;Department of Haematology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  • Deborah Schut Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  • Maja V. Maraldo Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  • Richard van der Maazen Department of Radiotherapy, Radboud University Medical Center, Nijmegen, The Netherlands
  • Lena Specht Department of Oncology, Section of Radiotherapy, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; ;Department of Haematology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark

DOI:

https://doi.org/10.1080/0284186X.2017.1279750

Abstract

Background and purpose: In early-stage classical Hodgkin lymphoma (HL) the target volume nowadays consists of the volume of the originally involved nodes. Delineation of this volume on a post-chemotherapy CT-scan is challenging. We report on the interobserver variability in target volume definition and its impact on resulting treatment plans.

Materials and methods: Two representative cases were selected (1: male, stage IB, localization: left axilla; 2: female, stage IIB, localizations: mediastinum and bilateral neck). Eight experienced observers individually defined the clinical target volume (CTV) using involved-node radiotherapy (INRT) as defined by the EORTC-GELA guidelines for the H10 trial. A consensus contour was generated and the standard deviation computed. We investigated the overlap between observer and consensus contour [Sørensen-Dice coefficient (DSC)] and the magnitude of gross deviations between the surfaces of the observer and consensus contour (Hausdorff distance). 3D-conformal (3D-CRT) and intensity-modulated radiotherapy (IMRT) plans were calculated for each contour in order to investigate the impact of interobserver variability on each treatment modality. Similar target coverage was enforced for all plans.

Results: The median CTV was 120 cm3 (IQR: 95–173 cm3) for Case 1, and 255 cm3 (IQR: 183–293 cm3) for Case 2. DSC values were generally high (>0.7), and Hausdorff distances were about 30 mm. The SDs between all observer contours, providing an estimate of the systematic error associated with delineation uncertainty, ranged from 1.9 to 3.8 mm (median: 3.2 mm). Variations in mean dose resulting from different observer contours were small and were not higher in IMRT plans than in 3D-CRT plans.

Conclusions: We observed considerable differences in target volume delineation, but the systematic delineation uncertainty of around 3 mm is comparable to that reported in other tumour sites.

This report is a first step towards calculating an evidence-based planning target volume margin for INRT in HL.

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Published

2017-04-03

How to Cite

Aznar, M. C. ., Girinsky, T. ., Kiil Berthelsen, A. ., Aleman, B. ., Beijert, M. ., Hutchings, M. ., … Specht, L. . (2017). Interobserver delineation uncertainty in involved-node radiation therapy (INRT) for early-stage Hodgkin lymphoma: on behalf of the Radiotherapy Committee of the EORTC lymphoma group. Acta Oncologica, 56(4), 608–613. https://doi.org/10.1080/0284186X.2017.1279750

Issue

Vol. 56 No. 4 (2017): Acta Oncologica

Section

Articles