Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
Division of Radiation Oncology, Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
BJU Int. 2022 Mar;129(3):337-344. doi: 10.1111/bju.15572. Epub 2021 Sep 2.
To determine the influence of rectal hydrogel spacer placement (HSP) on late rectal toxicity outcomes in prostate cancer patients treated with low-dose-rate (LDR) brachytherapy, with or without supplemental external beam radiotherapy (EBRT).
A total of 224 patients underwent LDR brachytherapy with HSP, as monotherapy or combined with EBRT, between January 2016 and December 2019. Dosimetric variables reflecting the extent of rectal sparing and late rectal toxicity outcomes were evaluated. This spacer cohort was retrospectively compared to a similar patient group (n = 139) in whom HSP was not used.
Hydrogel spacer placement was associated with significantly reduced rectal doses for all dosimetric variables; the median percentage rectal dose to 1 cc of rectum and rectal dose to 2 cc of rectum of the spacer cohort were all significantly lower compared to the non-spacer cohort. The incidence rates of overall (any grade) and grade ≥2 rectal toxicity were lower in patients with HSP compared to patients who did not undergo HSP: 12% and 1.8% vs 31% and 5.8%, respectively. The 3-year cumulative incidence of overall rectal toxicity was significantly lower with HSP than without (15% vs 33%; P < 0.001), corresponding to an overall rectal toxicity reduction on univariable analysis (hazard ratio 0.45, 95% confidence interval 0.28-0.73; P = 0.001). In this patient cohort treated with prostate brachytherapy, none of the urethral dosimetric variables or the presence or absence of HSP was associated with late urinary toxicity.
Hydrogel rectal spacer placement is a safe procedure, associated with significantly reduced rectal dose. HSP translates to a decrease in overall late rectal toxicity in patients receiving dose-escalated brachytherapy-based procedures.
确定直肠水凝胶间隔器放置（HSP）对接受低剂量率（LDR）近距离放射治疗、联合或不联合补充外部束放射治疗（EBRT）的前列腺癌患者的晚期直肠毒性结局的影响。
共有 224 名患者于 2016 年 1 月至 2019 年 12 月期间接受了 HSP 单药治疗或联合 EBRT 的 LDR 近距离放射治疗。评估了反映直肠保护程度和晚期直肠毒性结局的剂量学变量。该间隔器队列与未使用 HSP 的类似患者组（n=139）进行了回顾性比较。
HSP 与所有剂量学变量的直肠剂量显著降低相关；间隔器队列的直肠 1cc 剂量和直肠 2cc 剂量的中位数百分比均显著低于非间隔器队列。与未接受 HSP 的患者相比，接受 HSP 的患者的总体（任何等级）和等级≥2 直肠毒性的发生率较低：分别为 12%和 1.8%比 31%和 5.8%。与未使用 HSP 相比，使用 HSP 的患者 3 年总直肠毒性的累积发生率显著降低（15%比 33%；P<0.001），这对应于单变量分析中总直肠毒性的降低（危险比 0.45，95%置信区间 0.28-0.73；P=0.001）。在接受前列腺近距离放射治疗的患者队列中，尿道剂量学变量或 HSP 的存在与否均与晚期尿毒性无关。
直肠水凝胶间隔器放置是一种安全的操作，与直肠剂量显著降低相关。HSP 可降低接受剂量递增的基于近距离放射治疗的治疗方案的患者的总体晚期直肠毒性。
