How to cite: Sylvester JE. “Risks and Complications of Rectal Spacers.” Grand Rounds in Urology. October 23, 2025. Accessed
. https://grandroundsinurology.com/risks-and-complications-of-rectal-spacers/
Summary
John E. Sylvester, MD, FABS, Radiation Oncologist, Atlantic Urology Clinics, Myrtle Beach, South Carolina, critically examines the risks, limitations, and real-world complications associated with rectal spacers in prostate cancer radiation therapy. Dr. Sylvester reviews evidence from randomized clinical trials, registry data, and expert witness experience to evaluate whether rectal spacing consistently delivers a clinically meaningful benefit relative to its procedural risks.
Dr. Sylvester outlines the technical approaches and materials used for rectal spacing, including polyethylene glycol hydrogel, hyaluronic acid hydrogel, and balloon-based spacers, with emphasis on transperineal placement techniques. Results from pivotal randomized trials demonstrate consistent reductions in rectal dose and in grade 1 gastrointestinal toxicity, as measured by the Common Terminology Criteria for Adverse Events (CTCAE). There were no temporary reductions in acute grade 2 toxicity in one hypofractionation trial, and no reductions in grade 3 or higher toxicity were observed across studies.
Dr. Sylvester highlights discordance between physician-reported toxicity grading and patient-reported quality-of-life outcomes, noting that CTCAE grading does not always reflect patient bother. He notes that data from modern radiation trials without spacers demonstrate low rates of clinically significant rectal toxicity with contemporary planning and delivery techniques.
Dr. Sylvester focuses extensively on complications associated with spacer placement, particularly rectal wall infiltration caused by needle misplacement. He addresses manufacturer adverse event reporting data, with emphasis on underreporting and the severity of rare but devastating injuries, including fistulas, abscesses, colostomies, pelvic exenteration, and death.
Dr. Sylvester highlights that while rectal spacers reliably reduce rectal dose and low-grade toxicity, they introduce procedural risk, do not reduce severe toxicity, and may negatively impact quality of life. He emphasizes the importance of careful patient selection, transparent risk–benefit discussions, and physician expertise regarding spacer materials, placement, and technical approaches.
About the 28th Annual Southwest Prostate Cancer Symposium:
Presented by Program Chairs Nelson N. Stone, MD, Richard G. Stock, MD, and William K. Oh, MD, this conference educated attendees about advances in the management of localized and advanced prostate cancer, with a focus on imaging, technology, and training in the related devices. It included a scientific session, as well as live demonstrations of surgical techniques. You can learn more about the conference here.
ABOUT THE AUTHOR
John E. Sylvester, MD, FABS, is a Radiation Oncologist with Atlantic Urology Specialists in Myrtle Beach, South Carolina. Dr. Sylvester specializes in radiation oncology, genitourinary oncology, brachytherapy, IGRT, and radioactive isotope infusion. Dr. Sylvester co-founded the Seattle Prostate Institute in 1997, where he previously served as Director of Education and Training. He has also directed the Puget Sound Tumor Institute and has served as Chief Medical Officer of ProQura.
