An in-silico quality assurance study of contouring target volumes in thoracic tumors within a cooperative group setting

Hesham Elhalawani; Baher Elgohari; Timothy A Lin; Abdallah S R Mohamed; Thomas J Fitzgerald; Fran Laurie; Kenneth Ulin; Jayashree Kalpathy-Cramer; Thomas Guerrero; Emma B Holliday; Gregory Russo; Abhilasha Patel; William Jones; Gary V Walker; Musaddiq Awan; Mehee Choi; Roi Dagan; Omar Mahmoud; Anna Shapiro; Feng-Ming Spring Kong; Daniel Gomez; Jing Zeng; Roy Decker; Femke O B Spoelstra; Laurie E Gaspar; Lisa A Kachnic; Charles R Thomas Jr; Paul Okunieff; Clifton D Fuller

doi:10.1016/j.ctro.2019.01.001

An in-silico quality assurance study of contouring target volumes in thoracic tumors within a cooperative group setting

Clin Transl Radiat Oncol. 2019 Jan 6:15:83-92. doi: 10.1016/j.ctro.2019.01.001. eCollection 2019 Feb.

Authors

Hesham Elhalawani¹, Baher Elgohari¹, Timothy A Lin^{1

2}, Abdallah S R Mohamed^{1

3}, Thomas J Fitzgerald⁴, Fran Laurie⁴, Kenneth Ulin⁴, Jayashree Kalpathy-Cramer⁵, Thomas Guerrero⁶, Emma B Holliday¹, Gregory Russo⁷, Abhilasha Patel⁸, William Jones⁸, Gary V Walker^{1

9}, Musaddiq Awan¹⁰, Mehee Choi¹¹, Roi Dagan¹², Omar Mahmoud¹³, Anna Shapiro¹⁴, Feng-Ming Spring Kong¹⁵, Daniel Gomez¹, Jing Zeng¹⁶, Roy Decker¹⁷, Femke O B Spoelstra¹⁸, Laurie E Gaspar¹⁹, Lisa A Kachnic²⁰, Charles R Thomas Jr²¹, Paul Okunieff²², Clifton D Fuller¹

Affiliations

¹ Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, TX 77030, USA.
² Baylor College of Medicine, TX 77030, USA.
³ Department of Clinical Oncology and Nuclear Medicine, Alexandria University, Alexandria, Egypt.
⁴ Imaging and Radiation Oncology Core QA Center Rhode Island, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
⁵ Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Massachusetts, USA.
⁶ Department of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
⁷ Department of Radiation Oncology, Boston Medical Center, Massachusetts, USA.
⁸ Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, TX, USA.
⁹ Department of Radiation Oncology, Banner MD Anderson Cancer Center, Gilbert, Arizona, USA.
¹⁰ Department of Radiation Oncology, Case Western Reserve University, OH, USA.
¹¹ Department of Radiation Oncology, Northwestern University, IL, USA.
¹² University of Florida Health Proton Therapy Institute, FL, USA.
¹³ Department of Radiation Oncology, University of Miami, FL, USA.
¹⁴ Department of Radiation Oncology, Upstate Cancer Center, SUNY Upstate Medical University, NY, USA.
¹⁵ Department of Radiation Oncology, University Hospitals Cleveland Medical Center, OH, USA.
¹⁶ Department of Radiation Oncology, University of Washington Medical Center, WA, USA.
¹⁷ Department of Therapeutic Radiology, Yale University School of Medicine, Connecticut, USA.
¹⁸ Department of Radiation Oncology, Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, The Netherlands.
¹⁹ Department of Radiation Oncology, Vanderbilt University, TN, USA.
²⁰ Department of Radiation Oncology, Vanderbilt University Medical Center, Tennessee, USA.
²¹ Department of Radiation Medicine, Oregon Health & Science University, Oregon, USA.
²² SWOG, Department of Radiation Oncology, University of Florida College of Medicine, Florida, USA.

Abstract

Introduction: Target delineation variability is a significant technical impediment in multi-institutional trials which employ intensity modulated radiotherapy (IMRT), as there is a real potential for clinically meaningful variances that can impact the outcomes in clinical trials. The goal of this study is to determine the variability of target delineation among participants from different institutions as part of Southwest Oncology Group (SWOG) Radiotherapy Committee's multi-institutional in-silico quality assurance study in patients with Pancoast tumors as a "dry run" for trial implementation.

Methods: CT simulation scans were acquired from four patients with Pancoast tumor. Two patients had simulation 4D-CT and FDG-FDG PET-CT while two patients had 3D-CT and FDG-FDG PET-CT. Seventeen SWOG-affiliated physicians independently delineated target volumes defined as gross primary and nodal tumor volumes (GTV_P & GTV_N), clinical target volume (CTV), and planning target volume (PTV).Six board-certified thoracic radiation oncologists were designated as the 'Experts' for this study. Their delineations were used to create a simultaneous truth and performance level estimation (STAPLE) contours using ADMIRE software (Elekta AB, Sweden 2017). Individual participants' contours were then compared with Experts' STAPLE contours.

Results: When compared to the Experts' STAPLE, GTV_P had the best agreement among all participants, while GTV_N showed the lowest agreement among all participants. There were no statistically significant differences in all studied parameters for all TVs for cases with 4D-CT versus cases with 3D-CT simulation scans.

Conclusions: High degree of inter-observer variation was noted for all target volume except for GTV_P, unveiling potentials for protocol modification for subsequent clinically meaningful improvement in target definition. Various similarity indices exist that can be used to guide multi-institutional radiotherapy delineation QA credentialing.

Keywords: Contouring; Pancoast tumor; QA; Quality assurance; Target volumes; Thoracic.

Abstract

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