Prospective, Randomized Controlled Pivotal Trial of Biodegradable Balloon Rectal Spacer for Prostate Radiation...

Area of Science:

• Radiation Oncology
• Medical Devices
• Prostate Cancer Treatment

Background:

• Rectal spacers are used to mitigate rectal side effects during prostate radiation therapy.
• Concerns exist regarding the precision and reproducibility of current gel spacer injections.
• A novel rectoprostatic spacer balloon offers potential for controlled and adaptable deployment.

Purpose of the Study:

• To evaluate the efficacy and safety of a novel rectoprostatic spacer balloon.
• To test if the balloon spacer achieves ≥25% reduction in rectal V70 in >75% of subjects.
• To assess if implantation procedure-related and rectal adverse events are noninferior in balloon versus control groups.

Main Methods:

• 222 subjects with T1-T3 prostate cancer were enrolled and randomized (2:1 balloon:control).
• Patients underwent transperineal ultrasound-guided fiducial placement with or without the balloon spacer.
• Intensity-Modulated Radiation Therapy was delivered, with efficacy assessed via pre- and postimplant CT scans.

Main Results:

• The primary efficacy endpoint was met: 97.9% of balloon subjects achieved >25% rectal V70 reduction (P < .001).
• The primary safety endpoint was met, with fewer ≥grade 1 adverse events in balloon subjects (18% vs 23%, P < .001 for noninferiority).
• Mean perirectal spacing was 19 mm, and 98.5% of balloons resorbed by 6 months.

Conclusions:

• The biodegradable rectal spacer balloon effectively reduced rectal radiation dose.
• The balloon spacer was associated with decreased adverse events and consistent resorption.
• This novel device shows promise for improving safety and efficacy in prostate radiation therapy.