两分数立体定向放射治疗对局部前列腺癌的急性毒性和早期前列腺特异性抗原反应，使用SABR双重试验的直肠间距初始报告进行局部前列腺癌

SABR DUAL是一项具有初始I期安全队列的III期试验，该试验是2级立体定向放射疗法（SABR），具有可选的磁共振成像（MRI）基于基于局周间距的基于可选的磁共振成像（MRI）的焦点增强，用于局部前列腺癌。这代表了I期非随机队列的初步报告。主题具有有利的中间风险（FIR）或低风险前列腺腺癌，并且腺体体积<80 cc。所有在模拟之前都进行了放射性水凝胶间隔和基准标记的位置（计算机断层扫描和3-Tesla T2 MRI）。临床目标体积包括整个前列腺，在FIR患者中包括1-2 cm的精液囊泡。将2毫米的膨胀用于计划目标体积（PTV），并向PTV前端开了27 Gy的剂量，23 Gy对PTV囊泡囊泡，可选30 Gy同时提高MRI定义的显性优势病变。主要终点是根据扩大的前列腺癌指数复合26，国际前列腺症状评分和男性调查表性健康清单的3个月报告生活质量变化。次要终点是6个月的生活质量，急性毒性（使用不良事件的常见术语标准5.0版）和早期前列腺特异性抗原（PSA）反应。在I期同龄人中的20例患者中，有95％的患者患有FIR疾病，50％的患者同时获得了增强。在8个月的中值随访中，在1/20（5％），6/20（30％），2/20（10％），4/20（20％）和5/20（25％）的临床上发生了3个月至少重要的变化。国际前列腺症状评分平均增加了1±5.4，男性分数的性健康清单减少了1.8±6.5。 2级尿和肠毒性的发生率分别为10％和0％，没有≥3级毒性。最后随访时的平均PSA减少为70.4％±17.7％。使用直肠间距的2级前列腺SABR的这种可推广的方案是一种安全剂量降低的安全方法，具有最小的急性急性毒性。在SABR偶的III期随机部分中，研究了长期结局和与标准5分数SABR的直接比较。

SABR-Dual is a phase-III trial with an initial phase-I safety cohort, of 2-fraction stereotactic radiotherapy (SABR) with optional magnetic resonance imaging (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 prostate adenocarcinoma, and gland volume <80 cc. All underwent radiopaque hydrogel spacer and fiducial marker placement before simulation (computed tomography and 3-tesla T2 MRI). The clinical target volume included the entire prostate, and in FIR patients, 1-2 cm of seminal vesicle. A 2-mm 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-seminal vesicle, with an optional 30 Gy simultaneous boost to an MRI-defined dominant lesion. Primary endpoint was 3-month patient-reported changes in quality of life based on the Expanded Prostate Cancer Index Composite-26, International Prostate Symptom Score, and Sexual Health Inventory for Men questionnaires. Secondary endpoints were 6-month quality of life, acute toxicity (using Common Terminology Criteria for Adverse Events version 5.0) and early Prostate specific antigen (PSA) response.Among the 20 patients in the phase-I cohort, 95% had FIR disease, and 50% received a simultaneous boost. 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 International Prostate Symptom Score and decrease of 1.8 ± 6.5 in Sexual Health Inventory for Men scores. Rates of grade 2 urinary and bowel toxicity were 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 2-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.