How to cite: Hamstra DA. The Role of Spacing Devices in Modern Prostate XRT. Grand Rounds in Urology. September 19, 2025. Accessed Oct 2026. https://grandroundsinurology.com/the-role-of-spacing-devices-in-modern-prostate-xrt/
Summary
Daniel A. Hamstra, MD, PhD, FASTRO, FASCO, Professor and Chairman of Radiation Oncology, Baylor College of Medicine, Houston, Texas, provides an in-depth overview of the evolution and role of rectal spacer devices in prostate cancer radiotherapy. He explains how minimizing rectal dose directly reduces gastrointestinal (GI) toxicity and improves bowel-related quality of life.
Dr. Hamstra describes the pivotal PEG Hydrogel (SpaceOAR) Phase 3 trial, which randomized patients to receive intensity-modulated radiation therapy with or without a rectal spacer. The trial demonstrated a substantial reduction in rectal V70, with long-term follow-up reporting improved bowel quality of life.
Dr. Hamstra also discusses unexpected secondary benefits, including reduced penile bulb dose, potentially mitigating radiation-related sexual dysfunction. Pooled analyses suggest preserved erectile function among men with baseline potency. However, he cautions that incorrect placement can cause serious complications.
He compares SpaceOAR to newer FDA-approved alternatives, such as a hyaluronic acid gel spacer (FDA 2022) and a biodegradable balloon spacer (FDA 2024). The hyaluronic acid system enables repositioning and reversibility with hyaluronidase, while the balloon design provides consistent separation without the risk of injection.
Economic data from Medicare and MarketScan cohorts indicate that rectal spacer use may be cost-effective.
Dr. Hamstra argues that while spacers are not required for all patients, they are particularly valuable for motivated individuals, those with bowel disease, or those prioritizing sexual and rectal function preservation.
About The 29th Annual Innovations in Urologic Practice:
Presented by co-chairs Mohit Khera, MD, MBA, MPH, and Michael Coburn, MD, FACS, the Innovations in Urologic Practice conference provides a detailed review and commentary on multiple genitourinary and urologic diseases. Among the featured oncological topics are bladder cancer and immunotherapies, as well as upper tract cancer management and prostate cancer, including state-of-the-art imaging, focal therapy, and MRI. Experts also discuss new tools and techniques for nephrectomy and treating advanced renal cell carcinoma. In terms of general urological approaches, the conference also includes pelvic reconstruction and trauma, men’s health topics like male infertility and sexual dysfunction, and ways to diagnose and treat infections in the urology patient.
For further educational activities from this conference, visit our collection page.
ABOUT THE AUTHOR
Daniel A. Hamstra, MD, PhD, FASTRO, FASCO, serves as a Professor and the Chairman of Radiation Oncology at Baylor College of Medicine, for the Dan L. Duncan Comprehensive Cancer Center in Houston, Texas. Dr. Hamstra’s research has focused on advanced radiation and MRI in the treatment of CNS and prostate cancers, focusing on patient-reported quality of life.
