磁共振引导下局部复发性前列腺癌 SBRT 再放疗：多中心回顾性分析。
Magnetic resonance guided SBRT reirradiation in locally recurrent prostate cancer: a multicentric retrospective analysis.
机构信息
Dipartimento di Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy.
Istituto di Radiologia, Università Cattolica del Sacro Cuore, Rome, Italy.
出版信息
Radiat Oncol. 2023 May 22;18(1):84. doi: 10.1186/s13014-023-02271-y.
AIMS
Reirradiation of prostate cancer (PC) local recurrences represents an emerging challenge for current radiotherapy. In this context, stereotactic body radiation therapy (SBRT) allows the delivery of high doses, with curative intent. Magnetic Resonance guided Radiation Therapy (MRgRT) has shown promising results in terms of safety, feasibility and efficacy of delivering SBRT thanks to the enhanced soft tissue contrast and the online adaptive workflow. This multicentric retrospective analysis evaluates the feasibility and efficacy of PC reirradiation, using a 0.35 T hybrid MR delivery unit.
METHODS
Patients affected by local recurrences of PC and treated in five institutions between 2019 and 2022 were retrospectively collected. All patients had undergone previous Radiation Therapy (RT) in definitive or adjuvant setting. Re-treatment MRgSBRT was delivered with a total dose ranging from 25 to 40 Gy in 5 fractions. Toxicity according to CTCAE v 5.0 and treatment response were assessed at the end of the treatment and at follow-up.
RESULTS
Eighteen patients were included in this analysis. All patients had previously undergone external beam radiation therapy (EBRT) up to a total dose of 59.36 to 80 Gy. Median cumulative biologically effective dose (BED) of SBRT re-treatment was 213,3 Gy (103,1-560), considering an α/β of 1.5. Complete response was achieved in 4 patients (22.2%). No grade ≥ 2 acute genitourinary (GU) toxicity events were recorded, while gastrointestinal (GI) acute toxicity events occurred in 4 patients (22.2%).
CONCLUSION
The low rates of acute toxicity of this experience encourages considering MRgSBRT a feasibile therapeutic approach for the treatment of clinically relapsed PC. Accurate gating of target volumes, the online adaptive planning workflow and the high definition of MRI treatment images allow delivering high doses to the PTV while efficiently sparing organs at risk (OARs).
目的
前列腺癌（PC）局部复发的再放疗是当前放疗面临的一项新挑战。在这种情况下，立体定向体部放疗（SBRT）可以实现高剂量的治疗，具有治愈的意图。磁共振引导放疗（MRgRT）在安全性、可行性和 SBRT 疗效方面显示出了良好的结果，这要归功于增强的软组织对比度和在线自适应工作流程。这项多中心回顾性分析评估了使用 0.35 T 混合磁共振输送装置对 PC 进行再放疗的可行性和疗效。
方法
回顾性收集了 2019 年至 2022 年在五家机构接受局部复发 PC 治疗的患者。所有患者均在根治性或辅助治疗中接受过先前的放疗（RT）。再治疗的 MRgSBRT 采用 5 个分次的 25 至 40 Gy 总剂量进行。根据 CTCAE v5.0 评估毒性，在治疗结束和随访时评估治疗反应。
结果
这项分析纳入了 18 名患者。所有患者先前均接受过外照射放疗（EBRT），总剂量高达 59.36 至 80 Gy。SBRT 再治疗的中位累积生物有效剂量（BED）为 213.3 Gy（103.1-560），考虑到 α/β 为 1.5。4 名患者（22.2%）达到完全缓解。未记录到任何 2 级及以上的急性泌尿生殖系统（GU）毒性事件，而 4 名患者（22.2%）发生了胃肠道（GI）急性毒性事件。
结论
该经验中急性毒性发生率低，这鼓励将 MRgSBRT 视为治疗临床复发 PC 的一种可行治疗方法。靶区的精确门控、在线自适应计划工作流程以及 MRI 治疗图像的高分辨率允许向 PTV 提供高剂量，同时有效地保护危及器官（OARs）。
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