Published online May 15, 2022. doi: 10.4251/wjgo.v14.i5.1027
Peer-review started: December 10, 2021
First decision: January 12, 2022
Revised: January 24, 2022
Accepted: April 24, 2022
Article in press: April 24, 2022
Published online: May 15, 2022
Accurate target volume delineation is essential for precise radiotherapy. Inappropriate target volume may reduce local control or bring more normal tissue damage. However, defining a radiation field is not easy since it requires an integration of knowledge from multiple disciplines and rich clinical experience.
Previous studies have proved that wide variations in clinical target volume (CTV) delineation for rectal cancer were present among radiation oncologists despite the availability of several guidelines. Thus, how to improve the delineation accuracy and consistency has emerged as a key question in the era of precise radiotherapy. However, no study regarding the current situation of CTV delineation for rectal cancer is available in China, and there is also a lack of study on the impact of educational interventions on rectal cancer target delineation.
To examine the interobserver variation (IOV) in CTV delineation for rectal cancer among radiation oncologists in mainland China and evaluate whether an education program could improve the accuracy and consistency of delineation.
The study consisted of a baseline CTV delineation, a 150-min education intervention, and a follow-up CTV delineation. CTVs contoured by the participants before and after the program were obtained and compared. Quantitative evaluation included the indices for measuring the delineation accuracy of the participants relative to the standard contour and the indices for assessing IOV. Qualitative analysis included four common problems in CTV delineation.
Eighteen radiation oncologists from 10 provinces in China attended the education program and 13 of them completed two sets of CTVs. After the education program, a statistically significant reduction in the average volume of the delineated CTVs was detected (P = 0.001). The agreement between the participants’ delineation and the standard CTV improved remarkably and the IOV decreased. Qualitative analysis indicated that 61.54% of the participants (8/13) delineated the external iliac area, and 53.85% of the participants (7/13) delineated the ischiorectal fossa unnecessarily at the baseline, and the proportions reduced significantly after the program.
Our study first confirmed the wide variations in CTV delineation for rectal cancer among radiation oncologists from mainland China and proved that education interventions could improve the accuracy and consistency of delineation.
Further studies need to recruit more participants and include more cases for target volume delineation. Besides, the long-term effects of the education program also need to be investigated.