Interobserver variability in clinical target volume delineation for primary mediastinal B-cell lymphoma

Cristina Piva, Domenico Genovesi, Andrea Riccardo Filippi, Mario Balducci, Salvina Barra, Michela Buglione, Mario Busetto, Patrizia Ciammella, Paola Franzone, Vitaliana De Sanctis, Gabriele Simontacchi, Marco Fusella, Umberto Ricardi

Research output: Contribution to journalArticle


Purpose: The purpose of this study was to evaluate interobserver variability among radiation oncologists with experience in the field of lymphoma radiation therapy in the delineation of clinical target volume (CTV) in a challenging case of primary mediastinal B-cell lymphoma. Methods and materials: Ten experienced radiation oncologists were invited to a 1-day contouring session. The case of a 56-year-old man with primary mediastinal B-cell lymphoma with complete metabolic response after chemotherapy was chosen as the sample for the study. A brief presentation of his clinical history was given, together with guidelines for contouring. The 10 CTVs obtained were then compared in terms of variation in total volume and in craniocaudal, laterolateral, and anteroposterior diameters. The CTV with the best Dice similarity coefficient (DSC) between the union of all 10 CTVs and the individual CTV was considered the reference CTV, and the DSC and the Hausdorff distance (HD) for each volume compared with the reference CTV were then calculated. Results: A significant variability was found in total volume (mean, 498.3 cm3; range, 181.8-1003 cm3) and craniocaudal (median, 144.7 mm; range, 80.6-159 mm), laterolateral (median, 133.5 mm; range, 83.7-149.5 mm), and anteroposterior diameters (median, 136.2 mm; range, 84-150.5 mm). Analysis of the DSC and the HD showed a mean DSC of 0.53 (range, 0.31-0.74) and a mean HD of 6.4 cm (range, 1.8-14.8 cm). Conclusions: Results of this study strongly indicate the need to develop and share appropriate contouring guidelines among experts and suggest the promotion of specific educational activities to improve radiation therapy quality in both clinical trials and routine clinical practice.

Original languageEnglish
Pages (from-to)383-389
Number of pages7
JournalPractical Radiation Oncology
Issue number6
Publication statusPublished - Nov 1 2015


ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

Cite this

Piva, C., Genovesi, D., Filippi, A. R., Balducci, M., Barra, S., Buglione, M., Busetto, M., Ciammella, P., Franzone, P., De Sanctis, V., Simontacchi, G., Fusella, M., & Ricardi, U. (2015). Interobserver variability in clinical target volume delineation for primary mediastinal B-cell lymphoma. Practical Radiation Oncology, 5(6), 383-389.