Perirectal spacers theoretically reduce radiation dose to the rectum and adjacent structures during prostate radiation therapy and may reduce genitourinary toxicity. However, large-scale studies evaluating clinical outcomes associated with spacer placement outside of clinical trial settings remain limited.
Using the Merative MarketScan™ Commercial and Medicare Databases, we identified individuals who underwent radiotherapy for prostate cancer from 2016 to 2022. Those who received a perirectal spacer prior to radiotherapy were compared with those who underwent radiotherapy without spacer placement. The primary outcomes were genitourinary and rectal toxicities within 12 months of treatment. Multivariable Cox proportional hazards models were constructed adjusting for age, comorbidity, insurance type, androgen deprivation therapy use, and radiotherapy modality. Twelve-month total healthcare costs were compared between groups.
Among 32,319 eligible patients, 5,964 (18%) received a perirectal spacer. Perirectal spacer was associated with lower one-year incidence and hazard of all-cause urinary toxicity (18.6% vs 21.5%, HR 0.88, 95% CI: 0.83-0.93, p<0.01), urinary incontinence (13.8% vs 16.2%, HR 0.89, 95% CI: 0.83-0.95,p<0.01), and urinary tract infections (5.6% vs 6.3%, HR 0.86, 95% CI 0.78-0.96, p<0.01). Receipt of a perirectal spacer was not associated with significantly improved all-cause rectal toxicity (HR 0.94, 95% CI 0.87-1.01, p=0.09). Twelve-month total healthcare costs were lower in the spacer group ($35,417 vs $43,514; p<0.001).
In this large observational claims-based study, perirectal spacer use during prostate radiotherapy was associated with reduced short-term urinary toxicities and healthcare costs, but not with a statistically significant difference in rectal toxicity, the primary FDA-approved indication.
Urology practice. 2026 Mar 11 [Epub ahead of print]
Peter S Palencia, Xiangyi Xi, Xiwen Zhao, Brandon Ward, Shayan Smani, Nethusan Sivanesan, Gabriela M Diaz, Marcin Miszczyk, Tamas Fazekas, Pawel Rajwa, Jaime A Cavallo, Sanjay Aneja, Yi An, Isaac Y Kim, Michael S Leapman
Department of Urology, Yale School of Medicine, New Haven, CT., Yale Center for Analytical Sciences, Yale University, New Haven, Connecticut., Department of Urology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria., Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT.