Gross Tumor Delineation in Esophageal Cancer on MRI Compared With 18F-FDG-PET/CT

Sophie E Vollenbrock; Marlies E Nowee; Francine E M Voncken; Alexis N T J Kotte; Lucas Goense; Peter S N van Rossum; Astrid L H M W van Lier; Stijn W Heijmink; Annemarieke Bartels-Rutten; Frank J Wessels; Berthe M P Aleman; Luc Dewit; Linda G W Kerkmeijer; Edwin P M Jansen; Martijn Intven; Irene M Lips; Gert J Meijer; Jasper Nijkamp

doi:10.1016/j.adro.2019.04.004

Gross Tumor Delineation in Esophageal Cancer on MRI Compared With ¹⁸F-FDG-PET/CT

Adv Radiat Oncol. 2019 Apr 24;4(4):596-604. doi: 10.1016/j.adro.2019.04.004. eCollection 2019 Oct-Dec.

Authors

Sophie E Vollenbrock¹, Marlies E Nowee², Francine E M Voncken², Alexis N T J Kotte³, Lucas Goense^{3

4}, Peter S N van Rossum³, Astrid L H M W van Lier³, Stijn W Heijmink¹, Annemarieke Bartels-Rutten¹, Frank J Wessels⁵, Berthe M P Aleman², Luc Dewit², Linda G W Kerkmeijer³, Edwin P M Jansen², Martijn Intven³, Irene M Lips^{3

6}, Gert J Meijer³, Jasper Nijkamp^{2

7}

Affiliations

¹ Department of Radiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
² Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
³ Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.
⁴ Department of Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.
⁵ Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
⁶ Department of Radiation Oncology, Leiden University Medical Center, Leiden, The Netherlands.
⁷ Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands.

Abstract

Purpose: Current delineation of the gross tumor volume (GTV) in esophageal cancer relies on computed tomography (CT) and combination with ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET). There is increasing interest in integrating magnetic resonance imaging (MRI) in radiation treatment, which can potentially obviate CT- or FDG-PET/CT-based delineation. The aim of this study is to evaluate the feasibility of target delineation on T2-weighted (T2W) MRI and T2W including diffusion-weighted MRI (T2W + DW-MRI) compared with current-practice FDG-PET/CT.

Methods: Ten observers delineated primary esophageal tumor GTVs of 6 patients on FDG-PET/CT, T2W-MRI, and T2W + DW-MRI. GTVs, generalized conformity indices, in-slice delineation variation (root mean square), and standard deviations in the position of the most cranial and caudal delineated slice were calculated.

Results: Delineations on MRI showed smaller GTVs compared with FDG-PET/CT-based delineations. The main variation was seen at the cranial and caudal border. No differences were observed in conformity indices (FDG-PET/CT, 0.68; T2W-MRI, 0.66; T2W + DW-MRI, 0.68) and in-slice variation (root mean square, 0.13 cm on FDG-PET/CT; 0.10 cm on T2W-MRI; 0.14 cm on T2W + DW-MRI). In the 2 tumors involving the gastroesophageal junction, addition of DW-MRI to T2W-MRI significantly decreased caudal border variation.

Conclusions: MRI-based target delineation of the esophageal tumor is feasible with interobserver variability comparable to that with FDG-PET/CT, despite limited experience with delineation on MRI. Most variation was seen at cranial-caudal borders, and addition of DW-MRI to T2W-MRI may reduce caudal delineation variation of gastroesophageal junction tumors.