Dapartment of Radiotherapy and Radio-Oncology, LKH Salzburg University Clinics, Paracelsus Medical University, Müllner Hauptstraße 48, 5020, Salzburg, Austria.
Department of Urology, LKH Salzburg University Clinics, Paracelsus Medical University, Müllner Hauptstraße 48, 5020, Salzburg, Austria.
Radiat Oncol. 2019 Mar 15;14(1):47. doi: 10.1186/s13014-019-1248-6.
Rectal spacers are used to limit dose to the anterior rectal wall in high dose external beam radiation therapy of the prostate and have been shown to reduce radiation induced toxicity. Here we report the complication rate and toxicity of the implantation procedure in a large cohort of patients who have either received a gel- or balloon-type spacer.
In total, 403 patients received rectal spacing, 264 with balloon, 139 with gel. Allocation was non-randomized. Two hundred seventy-six patients were treated with normofractionated regimen, the remaining 125 patients in moderate hypofractionation. Spacer related acute and late rectal toxicity was prospectively assessed by endoscopy using a mucosa scoring system (Vienna Rectoscopy Score) as well as CTCAE V.4. For the balloon subgroup, position and rotation of balloon spacers were additionally correlated to incidence and grade of rectal reactions in a post-hoc analysis of post-implant planning MRIs.
Overall rectal toxicity was very low with average VRS scores of 0.06 at the day after implantation, 0.10 at the end of RT, 0.31 at 6 months and 0.42 at 12 months follow up. Acute Grade 3 toxicity (rectum perforation and urethral damage) directly related to the implantation procedure occurred in 1.49% (n = 6) and was seen exclusively in patients who had received the spacer balloon. Analysis of post implant MR imaging did not identify abnormal or mal-rotated positions of this spacer to be a predictive factors for the occurrence of spacer related G3 toxicities.
Spacer technology is an effective means to minimize dose to the anterior rectal wall. However, the benefits in terms of dose sparing need to be weighed against the low, but possible risks of complications such as rectum perforation.
直肠间隔器用于限制前列腺高剂量外照射放射治疗中前直肠壁的剂量，已被证明可降低放射性毒性。在这里，我们报告了在接受凝胶或球囊型间隔器的大队列患者中植入过程的并发症发生率和毒性。
共有 403 名患者接受了直肠间隔治疗，其中 264 名使用球囊，139 名使用凝胶。分配是非随机的。276 名患者接受常规分割治疗，其余 125 名患者接受中度低分割治疗。使用内窥镜通过粘膜评分系统（维也纳直肠镜评分）以及 CTCAE V.4 前瞻性评估间隔器相关的急性和晚期直肠毒性。对于球囊亚组，在植入后计划 MRI 的事后分析中，还将球囊间隔器的位置和旋转与直肠反应的发生率和等级相关联。
总体直肠毒性非常低，植入后第 1 天平均 VRS 评分 0.06，放射治疗结束时 0.10，6 个月时 0.31，12 个月时 0.42。与植入程序直接相关的急性 3 级毒性（直肠穿孔和尿道损伤）发生率为 1.49%（n=6），仅见于接受间隔器球囊的患者。植入后 MRI 分析未发现异常或错位的间隔器位置是导致间隔器相关 G3 毒性发生的预测因素。
间隔器技术是减少前直肠壁剂量的有效手段。然而，在剂量节约方面的好处需要与并发症（如直肠穿孔）的低但可能的风险进行权衡。
