Feasibility and Outcomes of Perirectal Spacer Implantation in Previously Treated Prostate Cancer Patients Undergoing Salvage Proton Therapy Radiation

IF 2.9 Q3 ONCOLOGY

Advances in Radiation Oncology Pub Date : 2026-03-01 Epub Date: 2026-02-09 DOI:10.1016/j.adro.2025.101985

Irini Yacoub MD , Keyur Mehta MD , Daniel Gorovets MD , Shaakir Hasan DO , J. Isabelle Choi MD , Arpit M. Chhabra MD , Stanislav Lazarev MD , Madhur Garg MD, MBA , Charles B. Simone II MD

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引用次数: 0

Abstract

Purpose

Treatment of recurrent prostate cancer following prior therapy is challenging due to the risk of toxicities to previously irradiated normal tissues, particularly the rectum. Proton therapy offers a conformal approach that may reduce this risk. Perirectal spacers have been shown to further minimize rectal dose in primary treatment, but the ability to be placed and their value in the retreatment setting have not been thoroughly evaluated to date. The purpose of this study was to evaluate feasibility of rectal spacer placement after prior pelvic radiation or other local treatments for prostate cancer.

Methods and Materials

We conducted a retrospective review of 30 consecutive patients with biopsy-confirmed, locally recurrent prostate adenocarcinoma treated with salvage proton therapy at the New York Proton Center (2020-2024). All patients had prior local therapies including high intensity focused ultrasound (HIFU), brachytherapy (BT), external beam radiation therapy (EBRT) or combination BT and EBRT, and underwent perirectal spacer placement (SpaceOAR or Barrigel). Spacer feasibility, maximum and minimum separation distances, rectal symmetry, rectal Dmax (% of prescription dose), and gastrointestinal toxicities were assessed. Toxicity was graded using Common Terminology Criteria for Adverse Events, version 5.0.

Results

Median patient age was 74 years, and the median time from prior therapy was 102 months. Spacer placement was successfully completed in 28 of 30 (93%) patients. Two placements were aborted due to excessive fibrosis. The median maximum and minimum midaxial anterior-posterior separations were 10.8 mm and 3.5 mm, respectively. Median rectal Dmax was 91.55% (range, 44%-102.4%). Seven patients had Dmax >100%, including 3 with prior HIFU. At a median follow-up of 12.5 months, gastrointestinal toxicities were limited to grade 1 diarrhea (n=3) No grade ≥ 2 toxicities or procedural complications were reported.

Conclusions

This is the first reported study evaluating the feasibility of perirectal spacer implantation in men with prior treatment to the pelvis, undergoing salvage radiation with protons. Our report shows perirectal spacer implantation is feasible and safe in patients undergoing salvage proton therapy, including those with prior EBRT or BT. Although technically more challenging in HIFU-treated patients, successful placement was achieved in the majority, with minimal toxicity and favorable dosimetric outcomes, although longer follow-up is needed.

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前列腺癌患者接受补救性质子治疗放疗后直肠周围植入间隔器的可行性和结果

目的前列腺癌复发后的治疗是具有挑战性的，因为以前照射过的正常组织，特别是直肠有毒性的风险。质子治疗提供了一种适形方法，可以降低这种风险。直肠周围间隔剂已被证明在初次治疗中可进一步减少直肠剂量，但其放置能力及其在再治疗环境中的价值迄今尚未得到彻底评估。本研究的目的是评估先前盆腔放疗或其他局部治疗前列腺癌后放置直肠垫片的可行性。方法和材料我们对纽约质子中心（2020-2024）连续30例活检确诊的局部复发前列腺癌患者进行了回顾性研究。所有患者之前都接受过局部治疗，包括高强度聚焦超声（HIFU）、近距离治疗（BT）、外束放射治疗（EBRT）或BT和EBRT联合治疗，并接受过直肠周围垫片放置（SpaceOAR或Barrigel）。评估间隔器的可行性、最大和最小分离距离、直肠对称性、直肠Dmax（处方剂量的百分比）和胃肠道毒性。使用不良事件通用术语标准5.0版本对毒性进行分级。结果患者中位年龄为74岁，中位治疗时间为102个月。30例患者中有28例（93%）成功完成了垫片放置。由于过度纤维化，2例植入流产。中间、最大、最小中轴前后分离分别为10.8 mm和3.5 mm。直肠中位Dmax为91.55%（范围：44%-102.4%）。7例患者Dmax为100%，其中3例既往HIFU。在12.5个月的中位随访中，胃肠道毒性仅限于1级腹泻（n=3），未报告≥2级毒性或手术并发症。结论：这是首次报道的研究，评估了在骨盆接受过补救性放射治疗的男性中植入直肠周围垫片的可行性。我们的报告显示，对于接受补偿性质子治疗的患者，包括既往有EBRT或BT的患者，直肠周围间隔器植入是可行且安全的。尽管在hifu治疗的患者中技术上更具挑战性，但大多数患者成功植入，毒性最小，剂量学结果良好，尽管需要更长时间的随访。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Advances in Radiation Oncology Medicine-Radiology, Nuclear Medicine and Imaging

CiteScore

4.60

自引率

4.30%

发文量

208

审稿时长

98 days

期刊介绍： The purpose of Advances is to provide information for clinicians who use radiation therapy by publishing: Clinical trial reports and reanalyses. Basic science original reports. Manuscripts examining health services research, comparative and cost effectiveness research, and systematic reviews. Case reports documenting unusual problems and solutions. High quality multi and single institutional series, as well as other novel retrospective hypothesis generating series. Timely critical reviews on important topics in radiation oncology, such as side effects. Articles reporting the natural history of disease and patterns of failure, particularly as they relate to treatment volume delineation. Articles on safety and quality in radiation therapy. Essays on clinical experience. Articles on practice transformation in radiation oncology, in particular: Aspects of health policy that may impact the future practice of radiation oncology. How information technology, such as data analytics and systems innovations, will change radiation oncology practice. Articles on imaging as they relate to radiation therapy treatment.