Reduced inter-observer and intra-observer delineation variation in esophageal cancer radiotherapy by use of fiducial markers.
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ICR Authors
Authors
Machiels, M
Jin, P
van Hooft, JE
Gurney-Champion, OJ
Jelvehgaran, P
Geijsen, ED
Jeene, PM
Willemijn Kolff, M
Oppedijk, V
Rasch, CRN
van Herk, MB
Alderliesten, T
Hulshof, MCCM
Jin, P
van Hooft, JE
Gurney-Champion, OJ
Jelvehgaran, P
Geijsen, ED
Jeene, PM
Willemijn Kolff, M
Oppedijk, V
Rasch, CRN
van Herk, MB
Alderliesten, T
Hulshof, MCCM
Document Type
Journal Article
Date
2019-06-03
Date Accepted
Abstract
Objective: Delineation variation of esophageal tumors remains a large source of geometric uncertainty. In the present study, we investigated the inter- and intra-observer variation in esophageal gross tumor volume (GTV) delineation and the impact of endoscopically implanted fiducial markers on these variations. Material/Methods: Ten esophageal cancer patients with at least two markers endoscopically implanted at the cranial and caudal tumor borders and visible on the planning computed tomography (pCT) were included in this study. Five dedicated gastrointestinal radiation oncologists independently delineated GTVs on the pCT without markers and with markers. The GTV was first delineated on pCTs where markers were digitally removed and next on the original pCT with markers. Both delineation series were executed twice to determine intra-observer variation. For both the inter- and intra-observer analyses, the generalized conformity index (CIgen), and the standard deviation (SD) of the distances between delineated surfaces (i.e., overall, longitudinal, and radial SDs) were calculated. Linear mixed-effect models were used to compare the without and with markers series (α = 0.05). Results: Both the inter- and intra-observer CIgen were significantly larger in the series with markers than in the series without markers (p < .001). For the series without markers vs. with markers, the inter-observer overall SD, longitudinal SD, and radial SD was 0.63 cm vs. 0.22 cm, 1.44 cm vs. 0.42 cm, and 0.26 cm vs. 0.18 cm, respectively (p < .05); moreover, the intra-observer overall SD, longitudinal SD, and radial SD was 0.45 cm vs. 0.26 cm, 1.10 cm vs. 0.41 cm, and 0.22 cm vs. 0.15 cm, respectively (p < .05). Conclusion: The presence of markers at the cranial and caudal tumor borders significantly reduced both inter- and intra-observer GTV delineation variation, especially in the longitudinal direction. Our results endorse the use of markers in GTV delineation for esophageal cancer patients.
Citation
Acta oncologica (Stockholm, Sweden), 2019, 58 (6), pp. 943 - 950
Source Title
Publisher
Medical Journal Sweden AB
ISSN
0284-186X
eISSN
1651-226X
Collections
Research Team
Radiotherapy Physics Modelling