SABR-Dual 是一项 III 期试验，具有初始 I 期安全队列，采用两部分立体定向放射治疗 (SABR) 和可选的基于 MRI 的局部增强，使用直肠周围间距，治疗局限性前列腺癌。这是来自 I 期非随机队列的初步报告。受试者患有有利的中度风险 (FIR) 或低度风险 (LR) 前列腺腺癌，且腺体体积 <80cc。在模拟（CT 和 3-tesla T2 MRI）之前，所有受试者都接受了不透射线的水凝胶垫片和基准标记放置。临床目标体积包括整个前列腺，在 FIR 患者中，包括 1-2 厘米的精囊 (SV)。应用 2mm 扩张来规划目标体积 (PTV)，并为 PTV-前列腺规定 27 Gy 的剂量，为 PTV-SV 规定 23 Gy 的剂量，并可选择对 MRI 定义的 30 Gy 同时增强 (SIB)显性病变。主要终点是患者根据 EPIC-26、IPSS 和 SHIM 问卷报告的 3 个月生活质量变化。次要终点是 6 个月的生活质量、急性毒性（使用 CTCAEv5）和早期 PSA 反应。 在 I 期队列的 20 名患者中，95% 患有 FIR 疾病，50% 接受 SIB。在中位随访 8 个月时，3 个月的最低临床重要变化发生率为 1/20 (5%)、6/20 (30%)、2/20 (10%)、4/20 (20%) ，5/20 (25%) 涉及尿失禁、尿路梗阻、肠道、性和激素领域。 IPSS 评分平均增加 1±5.4，SHIM 评分平均减少 1.8±6.5。 2 级泌尿和肠道毒性发生率分别为 10% 和 0%，没有 ≥3 级毒性。最后一次随访时的平均 PSA 下降为 70.4%±17.7%。这种使用直肠周围间距的两部分前列腺 SABR 的通用方案是超大分割剂量递增的安全方法，且急性毒性最小。 SABR-Dual 的 III 期随机部分正在研究长期结果以及与标准 5 分式 SABR 的直接比较。版权所有 © 2024。由 Elsevier Inc. 出版。

SABR-Dual is a phase III trial with an initial phase-I safety cohort, of two-fraction stereotactic radiotherapy (SABR) with optional MRI-based focal boost, using peri-rectal spacing, for localized prostate cancer. This represents the initial report from the phase-I non-randomized cohort.Subjects had favorable intermediate risk (FIR) or low risk (LR) prostate adenocarcinoma, and gland volume <80cc. All underwent radiopaque hydrogel spacer and fiducial marker placement prior to simulation (CT and 3-tesla T2 MRI). The clinical target volume included the entire prostate, and in FIR patients, 1-2cm of seminal vesicle (SV). A 2mm expansion was applied for planning target volume (PTV), and a dose of 27 Gy was prescribed to the PTV-prostate, 23 Gy to the PTV-SV, with an optional 30 Gy simultaneous boost (SIB) to an MRI-defined dominant lesion. Primary endpoint was 3-month patient-reported changes in quality of life based on the EPIC-26, IPSS, and SHIM questionnaires. Secondary endpoints were 6-month quality of life, acute toxicity (using CTCAEv5) and early PSA response.Among the 20 patients in the phase-I cohort, 95% had FIR disease, and 50% received an SIB. At median follow-up of 8 months, a 3-month minimally clinically important change occurred in 1/20 (5%), 6/20 (30%), 2/20 (10%), 4/20 (20%), and 5/20 (25%) in urinary incontinence, urinary obstructive, bowel, sexual, and hormonal domains. There was a mean increase of 1±5.4 in IPSS and decrease of 1.8±6.5 in SHIM scores. Rates of grade 2 urinary and bowel toxicity 10% and 0%, respectively, with no grade ≥3 toxicities. Mean PSA decrease at last follow-up was 70.4%±17.7%.This generalizable protocol of two-fraction prostate SABR using peri-rectal spacing is a safe approach for ultra-hypofractionated dose-escalation, with minimal acute toxicity. Longer-term outcomes and direct comparison with standard 5-fraction SABR are being studied in the phase-III randomized portion of SABR-Dual.Copyright © 2024. Published by Elsevier Inc.