Merino Lara Tomas Rodrigo, Fleury Emmanuelle, Mashouf Shahram, Helou Joelle, McCann Claire, Ruschin Mark, Kim Anthony, Makhani Nadiya, Ravi Ananth, Pignol Jean-Philippe
Radiotherapy Unit, School of Medicine, Pontificia Universidad Católica de Chile , Santiago , Chile ; Department of Radiation Oncology, Sunnybrook Odette Cancer Centre , Toronto, ON , Canada ; Department of Radiation Oncology, University of Toronto , Toronto, ON , Canada.
Department of Radiation Oncology, Sunnybrook Odette Cancer Centre , Toronto, ON , Canada ; Department of Radiation Oncology, University of Toronto , Toronto, ON , Canada.
Front Oncol. 2014 Oct 22;4:284. doi: 10.3389/fonc.2014.00284. eCollection 2014.
After breast conserving surgery, early stage breast cancer patients are currently treated with a wide range of radiation techniques including whole breast irradiation (WBI), accelerated partial breast irradiation (APBI) using high-dose rate (HDR) brachytherapy, or 3D-conformal radiotherapy (3D-CRT). This study compares the mean heart's doses for a left breast irradiated with different breast techniques. An anthropomorphic Rando phantom was modified with gelatin-based breast of different sizes and tumors located medially or laterally. The breasts were treated with WBI, 3D-CRT, or HDR APBI. The heart's mean doses were measured with Gafchromic films and controlled with optically stimulated luminescent dosimeters. Following the model reported by Darby (1), major cardiac were estimated assuming a linear risk increase with the mean dose to the heart of 7.4% per gray. WBI lead to the highest mean heart dose (2.99 Gy) compared to 3D-CRT APBI (0.51 Gy), multicatheter (1.58 Gy), and balloon HDR (2.17 Gy) for a medially located tumor. This translated into long-term coronary event increases of 22, 3.8, 11.7, and 16% respectively. The sensitivity analysis showed that the tumor location had almost no effect on the mean heart dose for 3D-CRT APBI and a minimal impact for HDR APBI. In case of WBI large breast size and set-up errors lead to sharp increases of the mean heart dose. Its value reached 10.79 Gy for women with large breast and a set-up error of 1.5 cm. Such a high value could increase the risk of having long-term coronary events by 80%. Comparison among different irradiation techniques demonstrates that 3D-CRT APBI appears to be the safest one with less probability of having cardiovascular events in the future. A sensitivity analysis showed that WBI is the most challenging technique for patients with large breasts or when significant set-up errors are anticipated. In those cases, additional heart shielding techniques are required.
保乳手术后，早期乳腺癌患者目前接受多种放疗技术治疗，包括全乳照射（WBI）、使用高剂量率（HDR）近距离放疗的加速部分乳腺照射（APBI）或三维适形放疗（3D-CRT）。本研究比较了不同乳腺放疗技术照射左乳时心脏的平均剂量。使用基于明胶的不同大小乳房以及位于内侧或外侧的肿瘤对拟人化的兰多体模进行了修改。对乳房进行WBI、3D-CRT或HDR APBI治疗。使用放射变色胶片测量心脏的平均剂量，并使用光激发发光剂量计进行对照。按照达比（1）报告的模型，假设主要心脏事件随着心脏平均剂量每格雷7.4%的线性风险增加进行估计。对于位于内侧的肿瘤，与3D-CRT APBI（0.51 Gy）、多导管（1.58 Gy）和球囊HDR（2.17 Gy）相比，WBI导致的心脏平均剂量最高（2.99 Gy）。这分别转化为长期冠状动脉事件增加22%、3.8%、11.7%和16%。敏感性分析表明，肿瘤位置对3D-CRT APBI的心脏平均剂量几乎没有影响，对HDR APBI的影响最小。在WBI情况下，乳房尺寸大以及摆位误差会导致心脏平均剂量急剧增加。对于乳房大且摆位误差为1.5 cm的女性，其值达到10.79 Gy。如此高的值可能使长期冠状动脉事件的风险增加80%。不同照射技术之间的比较表明，3D-CRT APBI似乎是最安全的技术，未来发生心血管事件的可能性较小。敏感性分析表明，对于乳房大的患者或预期存在明显摆位误差时，WBI是最具挑战性的技术。在这些情况下，需要额外的心脏屏蔽技术。
