文章：

碳离子放疗治疗盆腔肉瘤/脊索瘤中的骶神经保留规划策略

Sacral-Nerve-Sparing Planning Strategy in Pelvic Sarcomas/Chordomas Treated with Carbon-Ion Radiotherapy

原文发布日期：26 March 2024

DOI: 10.3390/cancers16071284

类型: Article

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英文摘要：

To minimize radiation-induced lumbosacral neuropathy (RILSN), we employed sacral-nerve-sparing optimized carbon-ion therapy strategy (SNSo-CIRT) in treating 35 patients with pelvic sarcomas/chordomas. Plans were optimized using Local Effect Model-I (LEM-I), prescribed DRBE|LEM-I|D50%(median dose to HD-PTV) = 73.6 (70.4–76.8) Gy (RBE)/16 fractions. Sacral nerves were contoured between L5-S3 levels. DRBE|LEM-Ito 5% of sacral nerves-to-spare (outside HD-CTV) (DRBE|LEM-I|D5%) were restricted to <69 Gy (RBE). The median follow-up was 25 months (range of 2–53). Three patients (9%) developed late RILSN (≥G3) after an average period of 8 months post-CIRT. The RILSN-free survival at 2 years was 91% (CI, 81–100). With SNSo-CIRT, DRBE|LEM-I|D5%for sacral nerves-to-spare = 66.9 ± 1.9 Gy (RBE), maintaining DRBE|LEM-Ito 98% of HD-CTV (DRBE|LEM-I|D98%) = 70 ± 3.6 Gy (RBE). Two-year OS and LC were 100% and 93% (CI, 84–100), respectively. LETd and DRBEwith modified-microdosimetric kinetic model (mMKM) were recomputed retrospectively. DRBE|LEM-Iand DRBE|mMKMwere similar, but DRBE-filtered-LETd was higher in sacral nerves-to-spare in patients with RILSN than those without. At DRBE|LEM-Icutoff = 64 Gy (RBE), 2-year RILSN-free survival was 100% in patients with <12% of sacral nerves-to-spare voxels receiving LETd > 55 keV/µm than 75% (CI, 54–100) in those with ≥12% of voxels (p< 0.05). DRBE-filtered-LETd holds promise for the SNSo-CIRT strategy but requires longer follow-up for validation.

摘要翻译： 

为降低放射性腰骶神经丛病变（RILSN）风险，本研究对35例盆腔肉瘤/脊索瘤患者采用骶神经保护优化碳离子治疗策略（SNSo-CIRT）。治疗方案基于局部效应模型-I（LEM-I）进行优化，处方剂量DRBE|LEM-I|D50%（高危计划靶区中位剂量）设定为73.6（70.4-76.8）Gy（RBE）/16次分割。在L5-S3节段勾画骶神经轮廓，将需保护的骶神经（位于高危临床靶区外）5%体积所受剂量（DRBE|LEM-I|D5%）限制在<69 Gy（RBE）。中位随访时间为25个月（范围2-53个月）。3例患者（9%）在碳离子治疗后平均8个月出现晚期RILSN（≥3级）。2年无RILSN生存率为91%（置信区间81-100%）。通过SNSo-CIRT策略，需保护骶神经的DRBE|LEM-I|D5%为66.9±1.9 Gy（RBE），同时保持高危临床靶区98%体积剂量（DRBE|LEM-I|D98%）为70±3.6 Gy（RBE）。2年总生存率和局部控制率分别为100%和93%（置信区间84-100%）。研究回顾性重新计算了剂量平均线性能量传递（LETd）及基于改进微剂量动力学模型（mMKM）的DRBE。DRBE|LEM-I与DRBE|mMKM结果相似，但发生RILSN患者需保护骶神经区域的DRBE滤波LETd值显著高于未发生者。当DRBE|LEM-I截断值为64 Gy（RBE）时，需保护骶神经体素中接受LETd > 55 keV/µm的比例<12%的患者2年无RILSN生存率达100%，而该比例≥12%的患者仅为75%（置信区间54-100%）（p<0.05）。DRBE滤波LETd参数在SNSo-CIRT策略中具有应用潜力，但需更长期随访验证。

原文链接：

Sacral-Nerve-Sparing Planning Strategy in Pelvic Sarcomas/Chordomas Treated with Carbon-Ion Radiotherapy