Zhang Yang-Zi, Zhu Xiang-Gao, Song Ma-Xiaowei, Yao Kai-Ning, Li Shuai, Geng Jian-Hao, Wang Hong-Zhi, Li Yong-Heng, Cai Yong, Wang Wei-Hu
Department of Radiation Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, Beijing 100142, China.
World J Gastrointest Oncol. 2022 May 15;14(5):1027-1036. doi: 10.4251/wjgo.v14.i5.1027.
Accurate target volume delineation is the premise for the implementation of precise radiotherapy. Inadequate target volume delineation may diminish tumor control or increase toxicity. Although several clinical target volume (CTV) delineation guidelines for rectal cancer have been published in recent years, significant interobserver variation (IOV) in CTV delineation still exists among radiation oncologists. However, proper education may serve as a bridge that connects complex guidelines with clinical practice.
To examine whether an education program could improve the accuracy and consistency of preoperative radiotherapy CTV delineation for rectal cancer.
The study consisted of a baseline target volume delineation, a 150-min education intervention, and a follow-up evaluation. A 42-year-old man diagnosed with stage IIIC (T3N2bM0) rectal adenocarcinoma was selected for target volume delineation. CTVs obtained before and after the program were compared. Dice similarity coefficient (DSC), inclusiveness index (IncI), conformal index (CI), and relative volume difference [ΔV (%)] were analyzed to quantitatively evaluate the disparities between the participants' delineation and the standard CTV. Maximum volume ratio (MVR) and coefficient of variation (CV) were calculated to assess the IOV. Qualitative analysis included four common controversies in CTV delineation concerning the upper boundary of the target volume, external iliac area, groin area, and ischiorectal fossa.
Of the 18 radiation oncologists from 10 provinces in China, 13 completed two sets of CTVs. In quantitative analysis, the average CTV volume decreased from 809.82 cm to 705.21 cm ( = 0.001) after the education program. Regarding the indices for geometric comparison, the mean DSC, IncI, and CI increased significantly, while ΔV (%) decreased remarkably, indicating improved agreement between participants' delineation and the standard CTV. Moreover, an 11.80% reduction in MVR and 18.19% reduction in CV were noted, demonstrating a smaller IOV in delineation after the education program. Regarding qualitative analysis, the greatest variations in baseline were observed at the external iliac area and ischiorectal fossa; 61.54% (8/13) and 53.85% (7/13) of the participants unnecessarily delineated the external iliac area and the ischiorectal fossa, respectively. However, the education program reduced these variations.
Wide variations in CTV delineation for rectal cancer are present among radiation oncologists in mainland China. A well-structured education program could improve delineation accuracy and reduce IOVs.
准确的靶区勾画是实施精确放疗的前提。靶区勾画不足可能会降低肿瘤控制率或增加毒性。尽管近年来已发布了多项直肠癌临床靶区（CTV）勾画指南，但放射肿瘤学家之间在CTV勾画方面仍存在显著的观察者间差异（IOV）。然而，适当的培训可能是连接复杂指南与临床实践的桥梁。
探讨一项培训计划是否能提高直肠癌术前放疗CTV勾画的准确性和一致性。
该研究包括一次基线靶区勾画、一次150分钟的培训干预以及一次随访评估。选择一名42岁诊断为IIIC期（T3N2bM0）直肠腺癌的男性进行靶区勾画。比较培训前后获得的CTV。分析骰子相似系数（DSC）、包容指数（IncI）、适形指数（CI）和相对体积差异[ΔV（%）]，以定量评估参与者勾画与标准CTV之间的差异。计算最大体积比（MVR）和变异系数（CV）以评估IOV。定性分析包括CTV勾画中关于靶区上界、髂外区域、腹股沟区和坐骨直肠窝的四个常见争议点。
来自中国10个省份的18名放射肿瘤学家中，13人完成了两组CTV。在定量分析中，培训计划后平均CTV体积从809.82 cm³降至705.21 cm³（P = 0.001）。关于几何比较指标，平均DSC、IncI和CI显著增加，而ΔV（%）显著降低，表明参与者勾画与标准CTV之间的一致性得到改善。此外，MVR降低了11.80%，CV降低了18.19%，表明培训计划后勾画的IOV更小。在定性分析中，基线时在髂外区域和坐骨直肠窝观察到最大差异；分别有61.54%（8/13）和53.85%（7/13）的参与者不必要地勾画了髂外区域和坐骨直肠窝。然而，培训计划减少了这些差异。
中国大陆放射肿瘤学家在直肠癌CTV勾画方面存在较大差异。一个结构完善的培训计划可以提高勾画准确性并减少IOV。
