Proposed Hydrogel-Implant Quality Score and a Matched-Pair Study for Prostate Radiation Therapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Urology

Background:

• SpaceOAR hydrogel is FDA-approved for reducing rectal toxicity during prostate radiation therapy.
• Current training lacks independent quality assessment, potentially impacting implant proficiency.
• Accurate hydrogel placement is crucial for maximizing rectal dose reduction.

Purpose of the Study:

• To introduce and validate the Hydrogel-Implant Quality Score (HIQS) for quantifying SpaceOAR placement accuracy.
• To assess the effectiveness of SpaceOAR in reducing rectal dose for low-dose-rate (LDR) brachytherapy patients.
• To correlate HIQS with clinical outcomes and identify areas for quality improvement.

Main Methods:

• A retrospective matched-pair study of 81 prostate patients undergoing LDR brachytherapy.
• SpaceOAR implantation performed under manufacturer supervision, followed by CT and MRI for planning.
• Development and application of the HIQS system to evaluate hydrogel placement quality.
• Comparison of intraoperative and postoperative rectal doses between SpaceOAR and non-SpaceOAR groups.

Main Results:

• The average HIQS was 77 ± 10.8, indicating variable placement quality.
• SpaceOAR significantly reduced rectal dose (ΔD2cc: 25.1 Gy, ΔD0.1cc: 65.7 Gy) compared to controls.
• Patients without rectal distortion and SpaceOAR experienced additional dose reductions.
• 17 cases showed rectal anatomic distortions, highlighting the need for quality monitoring.

Conclusions:

• The HIQS system effectively measures hydrogel placement quality and aids in assessing clinician performance.
• SpaceOAR hydrogel demonstrates significant rectal dose reduction benefits for LDR prostate brachytherapy patients.
• HIQS provides valuable insights for optimizing hydrogel implantation techniques and improving treatment outcomes.