It has been shown that magnetic resonance imaging (MRI) guidance versus computed tomography (CT) guidance for aggressive margin-reduction (AMR) for stereotactic body radiotherapy (SBRT) in prostate cancer reduces acute toxicity, but the longer-term benefits are unknown. We performed a secondary analysis of MIRAGE, a phase 3 randomized clinical trial of MRI-guided SBRT for prostate cancer, to determine whether AMR with MRI guidance significantly reduced 2-yr physician-scored or patient-reported toxic effects in comparison to CT guidance. The cumulative incidence of 2-yr physician-scored toxicity, defined as grade ≥2 genitourinary (GU) and gastrointestinal (GI) toxic effects according to Common Terminology Criteria for Adverse Events v4.03, were lower with MRI guidance. Cumulative incidence rates of late grade ≥2 toxicity at 2 yr with MRI-guided versus CT-guided SBRT were 27% (95% confidence interval [CI] 19–39%)] versus 51% (95% CI 41–63%) for GU toxicity (p = 0.004), and 1.4% (95% CI 0.2–9.6) versus 9.5% (95% CI 4.6–19) for GI toxicity (p = 0.025). Cumulative logistic regression revealed that MRI-guided SBRT was associated with significantly lower odds of a clinically relevant deterioration in bowel function according to the Expanded Prostate Cancer Index Composite-26 score (odds ratio 0.444, 95% CI 0.209–0.942; p = 0.035) and in the Sexual Health Inventory in Men score (odds ratio 0.366, 95% CI 0.148–0.906; p = 0.03). There were no significant differences in the odds of a deterioration for other quality-of-life metrics. These findings support the hypothesis that aggressive planning for margin reduction for prostate SBRT using MRI leads to continued reductions in toxic effects over 2-yr follow-up.This trial is registered on ClinicalTrials.gov Identifier as NCT04384770.

中文翻译：

---

磁共振成像与计算机断层扫描引导用于前列腺癌立体定向放疗：MIRAGE 随机临床试验的 2 年结果


已经表明，在前列腺癌立体定向放疗 （SBRT） 中，磁共振成像 （MRI） 引导与计算机断层扫描 （CT） 引导对立体定向放疗 （SBRT） 的积极切缘减少 （AMR） 可降低急性毒性，但长期益处尚不清楚。我们对 MIRAGE 进行了二次分析，这是一项 MRI 引导下前列腺癌 SBRT 的 3 期随机临床试验，以确定与 CT 引导相比，MRI 引导下的 AMR 是否显着降低了 2 年医生评分或患者报告的毒性作用。在 MRI 引导下，2 年医师评分毒性的累积发生率较低，定义为 ≥2 级泌尿生殖系统 （GU） 和胃肠道 （GI） 毒性作用，根据不良事件通用术语标准 v4.03。MRI 引导下与 CT 引导下 SBRT 在 2 年时晚期 ≥2 毒性的累积发生率为 27%（95% 置信区间 [CI] 19-39%）]，GU 毒性为 51%（95% CI 41-63%）（p = 0.004），胃肠道毒性为 1.4%（95% CI 0.2-9.6）和 9.5%（95% CI 4.6-19）（p = 0.025）。累积 logistic 回归显示，根据扩展前列腺癌指数综合 26 评分（比值比 0.444,95% CI 0.209-0.942;p = 0.035）和男性性健康量表评分（比值比 0.366,95% CI 0.148-0.906;p = 0.03）。其他生活质量指标恶化的几率没有显著差异。这些发现支持以下假设：使用 MRI 积极计划减少前列腺 SBRT 的切缘可在 2 年随访中持续减少毒性作用。此试用版在 ClinicalTrials.gov Identifier 上注册为 NCT04384770。