Department of Radiation Oncology, U.H. Sanchinarro. HM Hospitales, Calle Oña, 10, 28050, Madrid, Spain.
Department of Radiation Oncology, Fundación Valle del Lili, Cali, Colombia.
Clin Transl Oncol. 2021 Nov;23(11):2358-2367. doi: 10.1007/s12094-021-02636-3. Epub 2021 May 27.
To explore the feasibility of image-guided and respiratory-gated Stereotactic Body Radiation Therapy (SBRT) for Accelerated Partial Breast Irradiation (APBI) in patients with very early breast cancer.
Selected patients with early breast carcinoma after breast-conserving surgery were enrolled in this phase II trial. A fiducial marker was percutaneously placed close to surgical bed and five external fiducials were set on the skin. A CT scan for planning was acquired at free breathing. The treatment was planned and DVH were assessed according to international recommendations. Prescription dose was 30 Gy in five consecutive fractions of 6 Gy. A 6MV monoenergetic LINAC (linear accelerator) that combines stereoscopic X-ray imaging system and ExacTrac Adaptive Gating technique was used. PTV (planning target volume) intrafraction motion was controlled and PTV was irradiated in a selected gated area of the respiratory cycle. Shifts for a correct, gated set-up were calculated and automatically applied.
Between April 2013 and October 2015, a total of 23 patients were included. The median tumor size was 12 mm. The mean PTV volume was 114 cc. The mean ipsilateral lung V9 Gy was 2.2% and for left-sided breast cancers, the volume of the heart receiving 1.5 Gy was 11.5%. Maximum skin dose was 30.8 Gy. Acute toxicity was grade1 in all the patients and 100% experienced excellent/good breast cosmesis outcomes. With a median follow-up of 66 months (range 8-99 months) local-relapse-free-survival reaches 100%. One patient developed a second breast cancer outside the treated quadrant after 25.1 months.
APBI with SBRT and ExacTrac Adaptive Gating System was feasible. The acute and late toxicities were almost null and cosmesis was excellent. We also found that the margins of 5 mm applied from CTV to PTV were sufficient to compensate for geometric uncertainties.
探索在早期乳腺癌患者中，使用图像引导和呼吸门控立体定向体部放射治疗（SBRT）进行加速部分乳腺照射（APBI）的可行性。
本研究纳入了接受保乳手术后早期乳腺癌的患者。在手术床附近经皮植入一个基准标记物，并在皮肤上设置五个外部基准标记物。在自由呼吸时进行计划 CT 扫描。根据国际建议进行治疗计划和剂量体积直方图（DVH）评估。处方剂量为 30 Gy，分 5 次连续给予，每次 6 Gy。使用结合立体 X 射线成像系统和 ExacTrac 自适应门控技术的 6MV 单能直线加速器（linear accelerator）。PTV（计划靶区）内分次运动得到控制，在呼吸周期的选定门控区域内对 PTV 进行照射。计算并自动应用用于正确门控设置的移位。
2013 年 4 月至 2015 年 10 月，共纳入 23 例患者。肿瘤中位大小为 12mm。PTV 平均体积为 114cc。左乳癌患者的同侧肺 V9 Gy 平均值为 2.2%，心脏接受 1.5 Gy 照射的体积为 11.5%。最大皮肤剂量为 30.8Gy。所有患者的急性毒性均为 1 级，100%的患者获得了优秀/良好的乳房美容效果。中位随访时间为 66 个月（8-99 个月），局部无复发生存率达到 100%。1 例患者在 25.1 个月后在治疗象限外发生第二例乳腺癌。
SBRT 联合 ExacTrac 自适应门控系统行 APBI 是可行的。急性和迟发性毒性几乎为零，美容效果极佳。我们还发现，CTV 到 PTV 的 5mm 边缘足以补偿几何不确定性。
