Radiation Oncology, Azienda Sanitaria-Universitaria Friuli Centrale, Udine, Italy.
Radiation Oncology, IRCCS Regina Elena National Cancer Institute, Rome, Italy.
Int J Radiat Oncol Biol Phys. 2021 Sep 1;111(1):93-100. doi: 10.1016/j.ijrobp.2021.03.027. Epub 2021 Mar 19.
To assess the toxicity profile of prostate cancer stereotactic body radiation therapy (SBRT) in 3 fractions.
This was a prospective, multicenter phase 2 toxicity study enrolling patients with low to favorable intermediate-risk prostate cancer. Before simulation, 3 to 4 fiducial markers along with a rectal spacer were placed. The target (prostate only) was prescribed 40 Gy, whereas the maximum dose to the urethra was limited to 33 Gy with the highest priority at planning; less stringent objectives were placed on the bladder, the filling of which was controlled via a Foley catheter. Treatment was delivered every other day. Toxicity was prospectively scored with Common Terminology Criteria for Adverse Events, and several patient-reported outcomes were collected. The maximum allowed prevalence rate of grade 2+ genitourinary (GU) toxicity at 1 year was set at 15%, and the study was sized accordingly.
Between November 2015 and May 2019, 59 patients were enrolled by 3 participating institutions. Acute gastrointestinal toxicity was occasional and mild, whereas 11.9% of patients developed acute grade 2 GU toxicity and 1.7% developed acute grade 3 GU toxicity. No patient had persistent treatment-related grade 2+ GU toxicity at 12 months after SBRT; thus, the null hypothesis was rejected. We observed a clinically relevant worsening of both International Prostate Symptom Score (IPSS) and International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) scores at 12 months compared with baseline. Moreover, we found a strong association between all selected bladder dose/volume metrics at planning and ICIQ-SF worsening at 12 months, whereas for the IPSS, the correlation with bladder dose metrics was marginal.
The results suggest that at 12 months after treatment, the toxicity profile of SBRT in 3 fractions is acceptable.
评估前列腺癌立体定向体放射治疗（SBRT）3 个疗程的毒性概况。
这是一项前瞻性、多中心 2 期毒性研究，纳入了低至中危前列腺癌患者。在模拟前，放置 3 到 4 个基准标记物和直肠间隔器。靶区（仅前列腺）规定为 40Gy，而尿道的最大剂量限制为 33Gy，在计划中优先级最高；对膀胱的要求较不严格，通过 Foley 导管控制其充盈。隔天进行一次治疗。采用常见不良事件术语标准进行前瞻性毒性评分，并收集了几项患者报告的结果。将 1 年内 2+级以上泌尿生殖系统（GU）毒性的最大允许流行率设定为 15%，并据此进行了研究设计。
2015 年 11 月至 2019 年 5 月，3 家参与机构共纳入 59 例患者。急性胃肠道毒性偶尔出现且较轻，11.9%的患者出现急性 2 级 GU 毒性，1.7%的患者出现急性 3 级 GU 毒性。没有患者在 SBRT 后 12 个月出现持续的与治疗相关的 2+级 GU 毒性；因此，零假设被拒绝。与基线相比，我们观察到在 SBRT 后 12 个月时，国际前列腺症状评分（IPSS）和国际尿失禁咨询问卷-短表（ICIQ-SF）评分均有临床相关的恶化。此外，我们发现所有选定的膀胱剂量/体积指标与 12 个月时的 ICIQ-SF 恶化之间存在很强的相关性，而对于 IPSS，与膀胱剂量指标的相关性是边缘性的。
这些结果表明，在治疗后 12 个月，3 个疗程 SBRT 的毒性特征是可以接受的。
