Marzo Antonio Marco, Cozzi Luca, Franceschini Davide, Dominici Luca, Spoto Ruggero, Laurelli Francesco, Gallo Pasqualina, Paganini Lucia, Reggiori Giacomo, Brilli Federica, Caracciolo Alessandra, Franzese Ciro, Francone Marco, Scorsetti Marta
Radiotherapy and Radiosurgery Department, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Milan, Italy.
Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Milan, Italy.
Cancers (Basel). 2025 Jan 17;17(2):294. doi: 10.3390/cancers17020294.
Radiotherapy for thymoma is delivered post-operatively in selected cases. Given the particular location of the thymic bed and the excellent prognosis, late cardiac toxicities may be an issue. The purpose of this retrospective dosimetric study is to investigate whether intensity-modulated proton beam therapy (IMPT) compared to photon therapy could better spare cardiac substructures, given prespecified dose constraints.
We retrospectively selected patients treated with adjuvant radiotherapy for thymoma in our institution. We manually contoured fourteen cardiac substructures (CSs), with the supervision of a team of cardioradiologists. The photon-based plans were re-optimized in adherence to the volumetric modulated arc therapy (VMAT) technique with specific dose constraints for the new contoured structures. The proton-based plans were optimized in adherence to intensity-modulated proton therapy (IMPT) using the beam spot scanning technique.
Twenty-nine patients treated with adjuvant radiotherapy with a prescribed dose of 50 Gy in 25 daily fractions for radically resected thymoma were selected. IMPT demonstrated better sparing of most cardiac substructures in terms of Dmax, D and V. Finally, IMPT plans more easily achieved the proposed dose constraints.
Cardiac substructures can be successfully spared with IMPT. Clinical studies are needed to establish a relationship between dose parameters and the development of cardiac events.
胸腺瘤放疗在部分病例中于术后进行。鉴于胸腺床的特殊位置及良好的预后，晚期心脏毒性可能是一个问题。本回顾性剂量学研究的目的是，在给定预设剂量限制的情况下，研究与光子治疗相比，调强质子束治疗（IMPT）是否能更好地保护心脏亚结构。
我们回顾性选择了在本机构接受胸腺瘤辅助放疗的患者。在一组心脏放射科医生的监督下，我们手动勾勒了14个心脏亚结构（CSs）。基于光子的计划按照容积调强弧形放疗（VMAT）技术重新优化，对新勾勒的结构有特定的剂量限制。基于质子的计划按照调强质子治疗（IMPT），使用束斑扫描技术进行优化。
选择了29例接受辅助放疗的患者，对根治性切除的胸腺瘤给予50 Gy的处方剂量，分25次每日照射。在Dmax、D和V方面，IMPT显示出对大多数心脏亚结构更好的保护。最后，IMPT计划更容易达到建议的剂量限制。
IMPT能够成功保护心脏亚结构。需要开展临床研究以确定剂量参数与心脏事件发生之间的关系。
