Department of Radiation Oncology, Peking Union Medical College Hospital Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1 Shuaifuyuan Wangfujing Dongcheng District, Beijing, People's Republic of China.
Eight-year Medical Doctor Program, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China.
BMC Cancer. 2024 Oct 26;24(1):1321. doi: 10.1186/s12885-024-13076-x.
In patients undergoing breast-conserving therapy without surgical clip implantation, the accuracy of tumor bed identification and the consistency of clinical target volume (CTV) delineation under computed tomography (CT) simulation remain suboptimal. This study aimed to investigate the feasibility of implementing preoperative magnetic resonance (MR) simulation on delineations by assessing interobserver variability (IOV).
Preoperative MR and postoperative CT simulations were performed in patients who underwent breast-conserving surgery with no surgical clips implanted. Custom immobilization pads were used to ensure the same supine position. Three radiation oncologists independently delineated the CTV of tumor bed on the images acquired from MR and CT simulation registration and CT simulation alone. Cavity visualization score (CVS) was assigned to each patient based on the clarity of the tumor bed on CT simulation images. IOV was indicated by generalized conformity index (CI), denoted as CI and CI, and the distance between the centroid of mass (dCOM), denoted as dCOM and dCOM. The variation of IOV in different CVS subgroups was analyzed.
A total of 10 patients were enrolled in this study. The median and interquartile range (IQR) of maximum pathological diameter of the tumors in all patients were 1.55 (0.80-1.92) cm. No statistical significance was found between the volumes of CTVs on CT simulation and on MR/CT simulation registration images (p = 0.387). CI was significantly larger than CI (p = 0.005). dCOM was significantly smaller than dCOM (p = 0.037). The median and IQR of CVS in all patients were 2.34 (2.00-3.08). The difference of CI between CI and CI was larger in the low CVS group (p = 0.016). The difference of dCOM showed a decreasing trend when CVS was lower, although it did not reach statistical significance (p = 0.095).
For patients who underwent breast-conserving surgery without surgical clip implantation, the use of preoperative MR simulation in delineating the CTV of tumor bed decreased the IOV among observers. The consistency of tumor bed identification was improved especially in cases where the margins of tumor bed were challenging to visualize on CT simulation images. The study findings offer potential benefits in reducing local recurrence and minimizing tissue irritation in the surrounding areas. Future investigation in a larger patient cohort to validate our results is warranted.
在未行手术夹植入的保乳治疗患者中，在 CT 模拟下，肿瘤床的识别准确性和临床靶区（CTV）勾画的一致性仍不理想。本研究旨在通过评估观察者间变异性（IOV），探讨在术前磁共振（MR）模拟下进行勾画的可行性。
对未行手术夹植入的保乳手术后患者进行术前 MR 和术后 CT 模拟。使用定制的固定垫以确保相同的仰卧位。三位放射肿瘤学家分别在 MR 和 CT 模拟配准图像以及 CT 模拟图像上勾画肿瘤床的 CTV。根据 CT 模拟图像上肿瘤床的清晰度，为每位患者分配腔可视化评分（CVS）。IOV 由广义一致性指数（CI）表示，记为 CI 和 CI ，以及质量中心的距离（dCOM）表示，记为 dCOM 和 dCOM 。分析不同 CVS 亚组之间 IOV 的变化。
本研究共纳入 10 例患者。所有患者肿瘤的最大病理直径的中位数和四分位距（IQR）为 1.55（0.80-1.92）cm。CT 模拟和 MR/CT 模拟配准图像上的 CTV 体积之间无统计学差异（p=0.387）。CI 显著大于 CI （p=0.005）。dCOM 显著小于 dCOM （p=0.037）。所有患者的 CVS 的中位数和 IQR 为 2.34（2.00-3.08）。低 CVS 组 CI 与 CI 之间的差异较大（p=0.016）。当 CVS 较低时，dCOM 的差异呈下降趋势，但无统计学意义（p=0.095）。
对于未行手术夹植入的保乳手术后患者，术前 MR 模拟在勾画肿瘤床 CTV 方面降低了观察者间的 IOV。肿瘤床识别的一致性得到了改善，特别是在 CT 模拟图像上肿瘤床边缘难以可视化的情况下。本研究结果为降低局部复发率和减少周围组织刺激提供了潜在益处。需要在更大的患者队列中进行进一步研究来验证我们的结果。
