ARTO（ClinicalTrials.gov识别号：NCT03449719）是一项多中心、二期随机临床试验，旨在测试将立体定向体放疗（SBRT）添加到酮替雄酸乙酸酯和强的松（AAP）治疗中，对寡转移去势抵抗性前列腺癌（CRPC）患者的益处。所有患者均符合寡转移CRPC的定义，即非内脏转移病灶少于或等于3个。患者随机分配1:1接受仅接受AAP（对照组）或与AAP同时接受治疗部位的SBRT（实验组）。主要终点是生化反应率（BR），定义为治疗开始后6个月基线时的前列腺特异性抗原（PSA）降幅≥50%。完全生化反应（CBR），定义为治疗6个月后PSA<0.2ng/mL，以及无进展生存期（PFS）为次要终点。自2019年1月至2022年9月，共有157名患者入组。BR检测到79.6%的患者（实验组与对照组的比例分别为92%对68.3%），受试者比（OR）为5.34（95%置信区间，2.05至13.88；P = .001），有利于实验组。CBR检测到38.8%的患者（实验组与对照组的比例分别为56%对23.2%），OR为4.22（95%置信区间，2.12至8.38；P < .001）。SBRT显著改善了PFS，实验组与对照组的进展风险比为0.35（95%置信区间，0.21至0.57；P < .001）。该试验达到了生化控制和PFS的主要终点，表明在转移性去势抵抗性前列腺癌患者中，SBRT在一线AAP治疗外又具有临床优势。

ARTO (ClinicalTrials.gov identifier: NCT03449719) is a multicenter, phase II randomized clinical trial testing the benefit of adding stereotactic body radiation therapy (SBRT) to abiraterone acetate and prednisone (AAP) in patients with oligometastatic castrate-resistant prostate cancer (CRPC).All patients were affected by oligometastatic CRPC as defined as three or less nonvisceral metastatic lesions. Patients were randomly assigned 1:1 to receive either AAP alone (control arm) or AAP with concomitant SBRT to all the sites of disease (experimental arm). Primary end point was the rate of biochemical response (BR), defined as a prostate-specific antigen (PSA) decrease ≥50% from baseline measured at 6 months from treatment start. Complete BR (CBR), defined as PSA < 0.2 ng/mL at 6 months from treatment, and progression-free survival (PFS) were secondary end points.One hundred and fifty-seven patients were enrolled between January 2019 and September 2022. BR was detected in 79.6% of patients (92% v 68.3% in the experimental v control arm, respectively), with an odds ratio (OR) of 5.34 (95% CI, 2.05 to 13.88; P = .001) in favor of the experimental arm. CBR was detected in 38.8% of patients (56% v 23.2% in the experimental v control arm, respectively), with an OR of 4.22 (95% CI, 2.12 to 8.38; P < .001). SBRT yielded a significant PFS improvement, with a hazard ratio for progression of 0.35 (95% CI, 0.21 to 0.57; P < .001) in the experimental versus control arm.The trial reached its primary end point of biochemical control and PFS, suggesting a clinical advantage for SBRT in addition to first-line AAP treatment in patients with metastatic castration-resistant prostate cancer.