Sung SooYoon, Lee Joo Hwan, Lee Jong Hoon, Kim Sung Hwan, Kwak Yoo-Kang, Lee Sea-Won, Jeon Ye Won, Suh Young Jin
Department of Radiation Oncology, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.
Department of Surgery, St. Vincent's Hospital, The Catholic University of Korea College of Medicine, Suwon, Korea.
J Breast Cancer. 2016 Dec;19(4):417-422. doi: 10.4048/jbc.2016.19.4.417. Epub 2016 Dec 23.
Surgical clips are used as a target for postoperative breast radiotherapy, and displacement of surgical clips would result in inaccurate delivery of radiation. We investigated the displacement range of surgical clips in the breast during postoperative radiotherapy following breast-conserving surgery.
A total of 178 patients who received breast-conserving surgery and postoperative radiation of 59.4 Gy in 33 fractions to the involved breast for 6.5 weeks were included. Surgical clips were used to mark the lumpectomy cavity during breast-conserving surgery. Patients undertook planning computed tomography (CT) scan for whole breast irradiation. Five weeks after beginning radiation, when the irradiation dose was 45 Gy, planning CT scan was performed again for a boost radiotherapy plan in all patients. The surgical clips were defined in both CT images and compared in lateromedial (X), anteroposterior (Y), superoinferior (Z), and three-dimensional directions.
The 90th percentile of displacement of surgical clips was 5.31 mm (range, 0.0-22.2 mm) in the lateromedial direction, 7.1 mm (range, 0.0-14.2 mm) in the anteroposterior direction, and 6.0 mm (range, 0.0-10.0 mm) in the superoinferior direction. The 90th percentile of three-dimensional displacement distance was 9.8 mm (range, 0.0-28.2 mm). On the multivariate analysis, seroma ≥15 mL was the only independent factor associated with the displacement of surgical clips. In patients with seroma ≥15 mL, the 90th percentile of displacement of surgical clips was 15.1 mm in the lateromedial direction, 12.7 mm in the anteroposterior direction, 10.0 mm in the superoinferior direction, and 21.8 mm in the three-dimensional distance.
A target volume expansion of 10 mm from surgical clips may be sufficient to compensate for the displacement of clips during postoperative radiotherapy after breast-conserving surgery. For patients who had a seroma, a replanning CT scan for a boost radiation should be considered to ensure exact postoperative radiotherapy in breast cancer.
手术夹用作术后乳腺放疗的靶区，手术夹移位会导致放疗剂量不准确。我们研究了保乳手术后放疗期间乳腺内手术夹的移位范围。
纳入178例接受保乳手术且对患侧乳腺进行6.5周、分33次共59.4 Gy术后放疗的患者。保乳手术期间使用手术夹标记肿块切除腔。患者进行全乳照射的计划计算机断层扫描（CT）。放疗开始5周后，当照射剂量为45 Gy时，所有患者再次进行计划CT扫描以制定加量放疗计划。在两个CT图像中确定手术夹，并在内外侧（X）、前后位（Y）、上下位（Z）和三维方向上进行比较。
手术夹移位的第90百分位数在内外侧方向为5.31 mm（范围0.0 - 22.2 mm），前后位方向为7.1 mm（范围0.0 - 14.2 mm），上下位方向为6.0 mm（范围0.0 - 10.0 mm）。三维移位距离的第90百分位数为9.8 mm（范围0.0 - 28.2 mm）。多因素分析显示，血清肿≥15 mL是与手术夹移位相关的唯一独立因素。血清肿≥15 mL的患者中，手术夹移位的第90百分位数在内外侧方向为15.1 mm，前后位方向为12.7 mm，上下位方向为10.0 mm，三维距离为21.8 mm。
保乳手术后放疗期间，手术夹靶区外放10 mm可能足以补偿手术夹的移位。对于有血清肿的患者，应考虑重新进行计划CT扫描以制定加量放疗计划，以确保乳腺癌术后放疗的准确性。
