Primary tumor volume measurements in Ewing sarcoma: MRI inter- and intraobserver variability and comparison with FDG-PET

Authors

  • Ömer Kasalak Department of Radiology, Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
  • Jelle Overbosch Department of Radiology, Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
  • Andor W. J. M. Glaudemans Department of Radiology, Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
  • Ronald Boellaard Department of Radiology, Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
  • Paul C. Jutte Departments of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
  • Thomas C. Kwee Department of Radiology, Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands

DOI:

https://doi.org/10.1080/0284186X.2017.1410288

Abstract

Background: Primary tumor volume is as an important and independent prognostic factor in Ewing sarcoma. However, the observer variability of magnetic resonance imaging (MRI)-based primary tumor volume measurements in newly diagnosed Ewing sarcoma has never been investigated. Furthermore, it is unclear how MRI-based volume measurements compare to 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)-based volume measurements. This study aimed to determine the observer variability of simplified MRI-based primary tumor volume measurements in newly diagnosed treatment-naive Ewing sarcoma and to compare them to the actual primary tumor volume at MRI and the FDG-PET-based metabolically active tumor volume (MATV).

Material and methods: Twenty-nine newly diagnosed Ewing sarcoma patients with pretreatment MRI (of whom 11 also underwent FDG-PET) were included. Both exact and dichotomized (according to the proposed threshold of 200 mL) primary tumor volume measurements were analyzed.

Results: Mean inter- and intraobserver differences of MRI-based simplified tumor volume ± limits of agreement varied between 15–42 ± 155–204 mL and between 9–16 ± 64–250 mL, respectively. Inter- and intraobserver agreements of dichotomized MRI-based simplified tumor volume measurements was very good (κ = 0.827–1.000). Mean difference between simplified and actual tumor volumes at MRI ± limits of agreement was 60 ± 381 mL. Agreement between dichotomized simplified and actual tumor volumes at MRI was very good (κ = 0.839). Mean difference between MRI-based simplified tumor volume and MATV ± limits of agreement was 181 ± 549 mL and almost significantly different (p = .0581). Agreement between dichotomized MRI-based simplified tumor volume and MATV was moderate (κ = 0.560).

Conclusions: Exact MRI-based simplified primary tumor volume measurements in Ewing sarcoma suffer from considerable observer variability, but observer agreement of dichotomized measurements (≤200 mL vs. >200 mL) is very good and generally matches MRI-based actual volume measurements. MRI-based primary tumor volume measurements poorly-moderately agree with and tend to be higher than the MATV.

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Published

2018-04-03

How to Cite

Kasalak, Ömer, Overbosch, J., Glaudemans, A. W. J. M., Boellaard, R., Jutte, P. C., & Kwee, T. C. (2018). Primary tumor volume measurements in Ewing sarcoma: MRI inter- and intraobserver variability and comparison with FDG-PET. Acta Oncologica, 57(4), 563. https://doi.org/10.1080/0284186X.2017.1410288

Issue

Vol. 57 No. 4 (2018): Acta Oncologica

Section

Articles