Geometric contour variation in clinical target volume of axillary lymph nodes in breast cancer radiotherapy: an AIRO multi-institutional study

Maria Cristina Leonardi, Matteo Pepa, Simone Giovanni Gugliandolo, Rosa Luraschi, Sabrina Vigorito, Damaris Patricia Rojas, Maria Rosa La Porta, Domenico Cante, Edoardo Petrucci, Lorenza Marino, Giuseppina Borzì, Edy Ippolito, Maristella Marrocco, Alessandra Huscher, Matteo Chieregato, Angela Argenone, Luciano Iadanza, Fiorenza De Rose, Francesca Lobefalo, Francesca CucciarelliMarco Valenti, Maria Carmen De Santis, Anna Cavallo, Francesca Rossi, Serenella Russo, Agnese Prisco, Marika Guernieri, Roberta Guarnaccia, Tiziana Malatesta, Ilaria Meaglia, Marco Liotta, Paola Tabarelli de Fatis, Isabella Palumbo, Marta Marcantonini, Sarah Pia Colangione, Emilio Mezzenga, Sara Falivene, Maria Mormile, Vincenzo Ravo, Cecilia Arrichiello, Alessandra Fozza, Maria Paola Barbero, Giovanni Battista Ivaldi, Gianpiero Catalano, Cristiana Vidali, Cynthia Aristei, Caterina Giannitto, Eleonora Miglietta, Antonella Ciabattoni, Icro Meattini, Roberto Orecchia, Federica Cattani, Barbara Alicja Jereczek-Fossa

Research output: Contribution to journalArticlepeer-review


OBJECTIVES: To determine interobserver variability in axillary nodal contouring in breast cancer (BC) radiotherapy (RT) by comparing the clinical target volume of participating single centres (SC-CTV) with a gold-standard CTV (GS-CTV). METHODS: The GS-CTV of three patients (P1, P2, P3) with increasing complexity was created in DICOM format from the median contour of axillary CTVs drawn by BC experts, validated using the simultaneous truth and performance-level estimation and peer-reviewed. GS-CTVs were compared with the correspondent SC-CTVs drawn by radiation oncologists, using validated metrics and a total score (TS) integrating all of them. RESULTS: Eighteen RT centres participated in the study. Comparative analyses revealed that, on average, the SC-CTVs were smaller than GS-CTV for P1 and P2 (by -29.25% and -27.83%, respectively) and larger for P3 (by +12.53%). The mean Jaccard index was greater for P1 and P2 compared to P3, but the overlap extent value was around 0.50 or less. Regarding nodal levels, L4 showed the highest concordance with the GS. In the intra-patient comparison, L2 and L3 achieved lower TS than L4. Nodal levels showed discrepancy with GS, which was not statistically significant for P1, and negligible for P2, while P3 had the worst agreement. DICE similarity coefficient did not exceed the minimum threshold for agreement of 0.70 in all the measurements. CONCLUSIONS: Substantial differences were observed between SC- and GS-CTV, especially for P3 with altered arm setup. L2 and L3 were the most critical levels. The study highlighted these key points to address. ADVANCES IN KNOWLEDGE: The present study compares, by means of validated geometric indexes, manual segmentations of axillary lymph nodes in breast cancer from different observers and different institutions made on radiotherapy planning CT images. Assessing such variability is of paramount importance, as geometric uncertainties might lead to incorrect dosimetry and compromise oncological outcome.

Original languageEnglish
Pages (from-to)20201177
Number of pages1
JournalThe British journal of radiology
Issue number1123
Publication statusPublished - Jul 1 2021

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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