Use of a Biodegradable, Contrast-Filled Rectal Spacer Balloon in Intensity-Modulated Radiotherapy for Intermediate-Risk Prostate Cancer Patients: Dosimetric Gains in the BioPro-RCMI-1505 Study

Abstract

Background/purposeDose-escalated external beam radiotherapy (RT) is effective in the control of prostate cancer but is associated with a greater incidence of rectal adverse events. We assessed the dosimetric gain and safety profile associated with implantation of a new biodegradable rectal spacer balloon.Materials/methodsPatients scheduled for image-guided, intensity-modulated RT for intermediate-risk prostate cancer were prospectively included in the French multicenter BioPro-RCMI-1505 study (NCT02478112). We evaluated the dosimetric gain, implantation feasibility, adverse events (AEs), and prostate-cancer-specific quality of life associated with use of the balloon spacer.ResultsAfter a scheduled review of the initial recruitment target of 50 patients by the study’s independent data monitoring committee (IDMC), a total of 24 patients (including 22 with dosimetry data) were included by a single center between November 2016 and May 2018. The interventional radiologist who implanted the balloons considered that 86% of the procedures were easy. 20 of the 24 patients (83.3%) received IMRT and 4 (16.7%) received volumetric modulated arc therapy (78-80 Gy delivered in 39 fractions). The dosimetric gains associated with spacer implantation were highly significant (p<0.001) for most variables. For the rectum, the median (range) relative gain ranged from 15.4% (-9.2−47.5) for D20cc to 91.4% (36.8−100.0) for V70 Gy (%). 15 patients (62%) experienced an acute grade 1 AE, 8 (33%) experienced a late grade 1 AE, 1 (4.2%) experienced an acute grade 2 AE, and 3 experienced a late grade 2 AE. No grade 3 AEs were reported. Quality of life was good at baseline (except for sexual activity) and did not markedly worsen during RT and up to 24 months afterwards.ConclusionThe use of a biodegradable rectal spacer balloon is safe, effective and associated with dosimetric gains in modern RT for intermediate-risk prostate cancer.

Multicenter, dual fractionation scheme, single core lab comparison of rectal volume dose reduction following injection of two biodegradable perirectal spacers

“…Our findings comparable with the first results of the French multicenter open‐label study (BioPro‐RCMI‐1505) using the balloon spacer 13 . In this study reported by Latorzeff et al., 85.2% reduction in the mean rectal rV70 was achieved with the balloon spacer.…”

“…Data from the literature provides evidence for these spacer's safety profile, rectal dosimetric gain, and improved quality of life outcomes relative to prostate cancer patients treated with EBRT with no spacer. 3,13 However, there are differences in how the volume between the prostate and rectal interface is created based upon the devices themselves. The implantation procedure of the balloon spacer includes establishing a working channel along the plane from prostate apex to base using a beveled tip dilator dissection with an option for hydro dissection.…”

“…They are made of biodegradable material that mechanically creates a space, maintains that space for the entire course of prostate radiotherapy treatment and absorbed by the patient's body over time. Data from the literature provides evidence for these spacer's safety profile, rectal dosimetric gain, and improved quality of life outcomes relative to prostate cancer patients treated with EBRT with no spacer 3,13 …”

Long-term evaluation of the safety of a rectal-prostate spacer, the ProSpace® balloon, in patients treated with radiotherapy for prostate cancer

“…The selection of patients is important. In these studies, placement of a rectal-prostate spacer was contraindicated in patients at risk of capsular penetration or seminal vesicle invasion (14,15,37). No data exist at this time to support the safety of spacer use in patients with prostate cancer with capsular penetration or seminal vesicle invasion.…”

Application of Hydrogel Spacer SpaceOAR Vue for Prostate Radiotherapy

“…Another prostate rectal spacer that has been extensively studied in preclinical and clinical trials is the ProSpace biodegradable fillable balloon [ 54 , 55 ]. The ProSpace system—a deflated balloon made of biodegradable polymer—is placed perineally with hydrodissection and the use of an introducer.…”