Department of Physics, Carleton University, Ottawa, ON, Canada.
Radiation Oncology Section, Department of Oncology, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Saudi Arabia.
Breast Cancer Res Treat. 2021 Apr;186(2):343-352. doi: 10.1007/s10549-020-06086-3. Epub 2021 Jan 23.
Oncoplastic breast surgery (OBS) is gaining popularity among surgeons for breast-conserving surgery treatments. OBS relies on complex relocation and deformation of breast tissue involving the tumor bed (TB). In this study, we investigate the validity of using surgical clips with OBS for accurate TB delineation in adjuvant, targeted breast radiotherapy.
Different OBS techniques were simulated on realistic breast phantoms. Surgical clips were used to demarcate the TB. Following tumor resection and closure, the true TB (TB) was extracted. Each phantom was CT imaged at several phases of surgery in order to record pre- and post-OBS closure surgical clip displacements. Two senior radiation oncologists (ROs) were asked to delineate TBs on CTs by relying on surgical clips placed as per standard protocol, and by referring to operative notes. Their original contours, as well as those expanded using 5-15 mm margins, were compared with the accurate TB using the dice similarity coefficient (DSC), Hausdorff Distance (HD), and over- and under-contoured volumes. Inter- and intra-RO contour agreements were also evaluated.
Post-OBS surgical clips were significantly displaced outside the original breast quadrant. Inter- and Intra-RO TB contours were consistent, yet systematically differed from TB (DSC values range = 0.38 to 0.69, and maximum HD range = 17.8 mm to 38.0 mm). Using expansion margins did not improve contour congruence and caused significant over-contoured volumes.
Following OBS, surgical clips alone are not reliable radiographic surrogates of TB locations and accurate TB delineation is challenging. For complex OBS cases, indication of any type of partial breast irradiation is very questionable.
保乳手术中的肿瘤整形（OBS）技术在乳腺肿瘤治疗中越来越受到外科医生的欢迎。OBS 依赖于涉及肿瘤床（TB）的乳房组织的复杂重定位和变形。在这项研究中，我们研究了在辅助性、靶向性乳腺癌放射治疗中，使用 OBS 手术夹对 TB 进行准确勾画的有效性。
在逼真的乳房模型上模拟了不同的 OBS 技术。使用手术夹来标记 TB。在肿瘤切除和闭合后，提取真实的 TB（TB）。为了记录 OBS 闭合前后手术夹的位移，对每个模型在手术的几个阶段进行 CT 成像。两位资深的放射肿瘤学家（RO）被要求根据标准方案放置手术夹来勾画 TB，并参考手术记录。将他们勾画的原始轮廓，以及使用 5-15mm 边界扩展的轮廓，与准确的 TB 进行比较，使用 Dice 相似系数（DSC）、Hausdorff 距离（HD）以及过度和不足勾画的体积来评估。同时还评估了 RO 之间和内部的勾画一致性。
OBS 后，手术夹明显移位到原始乳房象限之外。RO 之间和内部的 TB 轮廓是一致的，但系统上与 TB 不同（DSC 值范围为 0.38 至 0.69，最大 HD 值范围为 17.8 毫米至 38.0 毫米）。使用扩展边界并不能提高轮廓一致性，反而会导致过度勾画的体积显著增加。
OBS 后，单独使用手术夹不能作为 TB 位置的可靠影像学替代物，准确勾画 TB 具有挑战性。对于复杂的 OBS 病例，任何类型的部分乳房照射的指征都非常值得怀疑。
