Interobserver variability (between radiation oncologist and radiation therapist) in tumor bed contouring after breast-conserving surgery

Eliana La Rocca, Vanessa Lici, Tommaso Giandini, Francesca Bonfantini, Sarah Frasca, Michela Dispinzieri, Massimiliano Gennaro, Serena Di Cosimo, Laura Lozza, Emanuele Pignoli, Riccardo Valdagni, Maria Carmen De Santis

Research output: Contribution to journalArticlepeer-review


Purpose: To examine interobserver variability between the radiation oncologist (RTO) and the radiation therapist (RTT) in delineating the tumor bed (TB) in early breast cancer (BC). Methods: We retrospectively analyzed patients who received a radiotherapy boost to the TB. In a first group, the clinical target volume (CTV) for the boost was the surgical bed, defined by using surgical clips. In a second group, the CTV was defined by identifying a seroma cavity or a metallic find on the scar. These contours were compared in terms of volume, number of slices, and Dice similarity coefficient (DSC). Results: Forty patients were assessed: 20 had surgical clips (group 1) while the other 20 had none (group 2). There was no difference in the number of slices contoured by the 2 operators for group 1, but a statistically significant difference emerged in the volumes: the RTT identified a TB that was a mean 45% smaller than the one identified by the RTO. Random differences were found between the 2 operators for group 2. The TBs delineated for this group were significantly larger (P<0.05) than those identified by the RTT for group 1. The mean Dice value between the RTO’s and the RTT’s TBs was 0.69±0.07 (range 0.53–0.81) for group 1 and 0.37±0.18 (range 0–0.58) for group 2 (P<0.05). Conclusions: This study showed that the use of clips coincided with less interoperator variability. With appropriate training, the RTT may play an important part in the multidisciplinary radiotherapy team.

Original languageEnglish
Pages (from-to)210-215
Number of pages6
Issue number3
Publication statusPublished - Jun 1 2019


  • Breast cancer
  • interobserver variability
  • surgical clips
  • tumor bed delineation

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


Dive into the research topics of 'Interobserver variability (between radiation oncologist and radiation therapist) in tumor bed contouring after breast-conserving surgery'. Together they form a unique fingerprint.

Cite this