Interobserver variability in target volume delineation in definitive radiotherapy for thoracic esophageal cancer: a multi-center study from China.

Abstract

PURPOSE:

To investigate the interobserver variability (IOV) in target volume delineation of definitive radiotherapy for thoracic esophageal cancer (TEC) among cancer centers in China, and ultimately improve contouring consistency as much as possible to lay the foundation for multi-center prospective studies.

METHODS:

Sixteen cancer centers throughout China participated in this study. In Phase 1, three suitable cases with upper, middle, and lower TEC were chosen, and participants were asked to contour a group of gross tumor volume (GTV-T), nodal gross tumor volume (GTV-N) and clinical target volume (CTV) for each case based on their routine experience. In Phase 2, the same clinicians were instructed to follow a contouring protocol to re-contour another group of target volume. The variation of the target volume was analyzed and quantified using dice similarity coefficient (DSC).

RESULTS:

Sixteen clinicians provided routine volumes, whereas ten provided both routine and protocol volumes for each case. The IOV of routine GTV-N was the most striking in all cases, with the smallest DSC of 0.37 (95% CI 0.32-0.42), followed by CTV, whereas GTV-T showed high consistency. After following the protocol, the smallest DSC of GTV-N was improved to 0.64 (95% CI 0.45-0.83, P = 0.005) but the DSC of GTV-T and CTV remained constant in most cases.

CONCLUSION:

Variability in target volume delineation was observed, but it could be significantly reduced and controlled using mandatory interventions.

• Authors: Xiao Chang, Wei Deng, Xin Wang, Zongmei Zhou, Jun Yang, Wenling Guo, Miaoling Liu, Xiaolu Qi, Ling Li, Kaixian Zhang, Min Zhang, Yonggang Shi, Ke Liu, Yidian Zhao, Huitao Wang, Zhilong Yu, Jihong Zhang, Lihua Wang, Xueying Qiao, Chun Han, Shuchai Zhu, Ruohui Zhang, Junqiang Chen, Cairong Hu, Fuquan Zhang, Xiaorong Hou, Qingsong Pang, Wencheng Zhang, Gaofeng Li, Hailei Lin, Xinchen Sun, Xiaolin Ge, Caihong Li, Hong Ge, Dingjie Li, Yadi Wang, Na Lu, Xianshu Gao, Shangbin Qin, Yuan Tian, Zefen Xiao
• Journal: Radiation oncology (London, England) (Radiat Oncol) Vol. 16 Issue 1 Pg. 102 (Jun 09 2021) ISSN: 1748-717X [Electronic] England
• PMID: 34107984 (Publication Type: Journal Article, Multicenter Study)

Topics

• China
• Esophageal Neoplasms (pathology, radiotherapy)
• Humans
• Observer Variation
• Organs at Risk (radiation effects)
• Prognosis
• Radiotherapy Dosage
• Radiotherapy Planning, Computer-Assisted (standards)
• Radiotherapy, Intensity-Modulated (standards)
• Thoracic Neoplasms (pathology, radiotherapy)
• Tumor Burden