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Association of Perirectal Spacer Use with Complications and Hospital Admission Rates after Prostate Radiotherapy
Peter S. Palencia, BS1, Xiangyi Xi, PhD, MS
2, Xiwen Zhao, MS
2, Shayan Smani, BS
1, Nethusan Sivanesan, BS
1, Gabriela M. Diaz, MD
1, Marcin Miszyck, MD, PhD
3, Tamas Fazekas, MD
3, Pawel Rajwa, MD, PhD
3, Jaime Cavallo, MD, MPHS
1, Sanjay Aneja, MD
4, Yi An, MD
4, Isaac Y. Kim, MD, PhD
1, Michael S. Leapman, MD, MSPH
1.
1Department of Urology, Yale School of Medicine, New Haven, CT, USA,
2Yale Center for Analytical Sciences, Yale University, New Haven, CT, USA,
3Department of Urology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria,
4Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, USA.
BACKGROUND: Perirectal spacers may reduce toxicity from prostate radiotherapy by increasing distance between the prostate and organs at risk. Although prior studies have demonstrated reductions in rectal dose and toxicities, clinical outcomes in those treated in the real-world setting have not been evaluated at national scale. This study aims to assess clinical outcomes and toxicities in a national sample of individuals receiving prostate radiotherapy with and without a perirectal spacer.
METHODS: Within the Merative MarketScan Commercial and Medicare Databases, we identified beneficiaries with prostate cancer receiving prostate radiotherapy in 2016 through 2022. Beneficiaries were classified based on whether they underwent perirectal spacer placement. We compared the incidence of gastrointestinal, urinary, and sexual toxicities as well as hospital admission within 12 months of treatment between beneficiaries with perirectal spacer and those without.
RESULTS: We identified 47,734 eligible beneficiaries in the study period, including 6,681 (14.0%) with evidence of pre-treatment perirectal spacers and 41,053 (86.0%) without. One-year incidence of urinary tract infection (5.8% vs. 7.2%, p<0.001), urinary incontinence (0.9% vs. 1.9%, p<0.001), rectal toxicity (2.4% vs. 3.4%, p<0.001), and radiation proctitis (0.9% vs. 1.3%, p=0.01) were lower in beneficiaries with perirectal spacers compared to those without. No statistically significant differences were identified in the one-year incidence of hematuria, bowel obstruction, and sexual dysfunction (Table 1). One-year hospital admission rates were lower in beneficiaries with perirectal spacers (7.4% vs. 14.0%, p<0.001).
CONCLUSIONS: In this national observational study of beneficiaries receiving prostate radiotherapy, perirectal spacers were associated with lower incidence of select gastrointestinal and urinary toxicities, and hospital admissions. These findings should be complemented with patient reported measures to provide a better understanding of the effectiveness of these interventions.
One-year incidence of gastrointestinal, urinary, and sexual toxicities | | | No Perirectal Spacer
n=41,053 | | Perirectal Spacer
n=6,681 | | p-value |
| Urinary Tract Infection | | 2,948 (7.2%) | | 386 (5.8%) | | <0.001 |
| Hematuria | | 1,268 (3.1%) | | 180 (2.7%) | | 0.08 |
| Urinary Incontinence | | 788 (1.9%) | | 61 (0.9%) | | <0.001 |
| Rectal Toxicity | | 1,379 (3.4%) | | 158 (2.4%) | | <0.001 |
| Radiation Proctitis | | 529 (1.3%) | | 59 (0.9%) | | 0.01 |
| Bowel Obstruction | | 107 (0.3%) | | 11 (0.2%) | | 0.14 |
| Sexual Dysfunction | | 3,921 (9.6%) | | 658 (9.8%) | | 0.40 |
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