Abstract
Purpose: Accurate target definition is critical for the appropriate application of radiation therapy. In 2008, the Radiation Therapy Oncology Group (RTOG) published an international collaborative atlas to define the clinical target volume (CTV) for intensity modulated pelvic radiation therapy in the postoperative treatment of endometrial and cervical cancer. The current project is an updated consensus of CTV definitions, with removal of all references to bony landmarks and inclusion of the para-aortic and inferior obturator nodal regions. Methods and Materials: An international consensus guideline working group discussed modifications of the current atlas and areas of controversy. A document was prepared to assist in contouring definitions. A sample case abdominopelvic computed tomographic image was made available, on which experts contoured targets. Targets were analyzed for consistency of delineation using an expectation-maximization algorithm for simultaneous truth and performance level estimation with kappa statistics as a measure of agreement between observers. Results: Sixteen participants provided 13 sets of contours. Participants were asked to provide separate contours of the following areas: vaginal cuff, obturator, internal iliac, external iliac, presacral, common iliac, and para-aortic regions. There was substantial agreement for the common iliac region (sensitivity 0.71, specificity 0.981, kappa 0.64), moderate agreement in the external iliac, para-aortic, internal iliac and vaginal cuff regions (sensitivity 0.66, 0.74, 0.62, 0.59; specificity 0.989, 0.966, 0.986, 0.976; kappa 0.60, 0.58, 0.52, 0.47, respectively), and fair agreement in the presacral and obturator regions (sensitivity 0.55, 0.35; specificity 0.986, 0.988; kappa 0.36, 0.21, respectively). A 95% agreement contour was smoothed and a final contour atlas was produced according to consensus. Conclusions: Agreement among the participants was most consistent in the common iliac region and least in the presacral and obturator nodal regions. The consensus volumes formed the basis of the updated NRG/RTOG Oncology postoperative atlas. Continued patterns of recurrence research are encouraged to refine these volumes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 413-424 |
| Number of pages | 12 |
| Journal | International Journal of Radiation Oncology Biology Physics |
| Volume | 109 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 1 2021 |
Funding
Disclosures: N.A-R. reports grants paid to their institution from Stryker/Novadaq, Olympus, and Grail outside the submitted work and is funded in part by the National Institutes of Health/National Cancer Institute Memorial Sloan Kettering Cancer Center Support Grant (P30 CA008748). S.B. discloses the role of Assistant Medical Director for Via Oncology, and honoraria from Varian, Eisai, Xoft (DSMB), and the International Journal of Radiation Oncology. W.R.B. discloses an NCI IROC grant from the National Institutes of Health (NIH), during the time of the study. L.P. discloses advisory board and steering committee roles with BTG, Biocompatibles, an advisory board role with Sirtex, and moderator and speaker roles for ViewRay, outside the submitted work. W.S. discloses honoraria from Carl Zeiss, an advisory board role with Merck and Varian, and a cochair role with NRG Oncology, outside the submitted role. This project was supported by grants U10CA180868 ( NRG Oncology Operations ) and U10CA180822 ( NRG Oncology SDMC ) from the National Cancer Institute (NCI).
ASJC Scopus subject areas
- Radiation
- Oncology
- Radiology Nuclear Medicine and imaging
- Cancer Research
