Continued Benefit to Rectal Separation for Prostate Radiation Therapy: Final Results of a Phase III Trial

Journal Article · Sat Apr 01 00:00:00 EDT 2017 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2016.12.024· OSTI ID:22649887

Mariados, Neil ^[1]; Sylvester, John ^[2]; Shah, Dhiren ^[3]; Karsh, Lawrence ^[4]; Hudes, Richard ^[5]; Beyer, David ^[6]; Kurtzman, Steven ^[7]; Bogart, Jeffrey ^[8]; Hsi, R. Alex ^[9]; Kos, Michael ^[10]; Ellis, Rodney ^[11]; Logsdon, Mark ^[12]; Zimberg, Shawn ^[13]; Forsythe, Kevin ^[14]; Zhang, Hong ^[15]; Soffen, Edward ^[16]; Francke, Patrick ^[17]; Mantz, Constantine ^[18]; others, and

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1. Associated Medical Professionals of NY, PLLC, Syracuse, New York (United States)
2. 21st Century Oncology, Inc, Lakewood Ranch, East Bradenton, Florida (United States)
3. Western New York Urology Associates, LLC, Doing Business as Cancer Care of WNY, Cheektowaga, New York (United States)
4. The Urology Center of Colorado, Denver, Colorado (United States)
5. Chesapeake Urology Associates, Doing Business as Chesapeake Urology Research Associates (The Prostate Center), Owings Mills, Maryland (United States)
6. Arizona Oncology Services Foundation, Phoenix, Arizona (United States)
7. Urological Surgeons of Northern California Inc, Campbell, California (United States)
8. The Research Foundation of State University of New York/State University of New York Upstate Medical University, Syracuse, New York (United States)
9. Peninsula Cancer Center, Poulsbo, Washington (United States)
10. Urology Nevada, Reno, Nevada (United States)
11. University Hospitals Case Medical Center, Cleveland, Ohio (United States)
12. Sutter Health Sacramento Sierra Region, Doing Business as Sutter Institute for Medical Research, Sacramento, California (United States)
13. Advanced Radiation Centers of New York, Lake Success, New York (United States)
14. Oregon Urology Institute, Springfield, Oregon (United States)
15. University of Rochester, Rochester, New York (United States)
16. CentraState Medical Center, Freehold, New Jersey (United States)
17. Carolina Regional Cancer Center, LLC, 21st Century Oncology, Inc, Myrtle Beach, South Carolina (United States)
18. 21st Century Oncology, Inc, Fort Meyers, Florida (United States)

Purpose: SpaceOAR, a Food and Drug Administration–approved hydrogel intended to create a rectal–prostate space, was evaluated in a single-blind phase III trial of image guided intensity modulated radiation therapy. A total of 222 men were randomized 2:1 to the spacer or control group and received 79.2 Gy in 1.8-Gy fractions to the prostate with or without the seminal vesicles. The present study reports the final results with a median follow-up period of 3 years. Methods and Materials: Cumulative (Common Terminology Criteria for Adverse Events, version 4.0) toxicity was evaluated using the log-rank test. Quality of life (QOL) was examined using the Expanded Prostate Cancer Index Composite (EPIC), and the mean changes from baseline in the EPIC domains were tested using repeated measures models. The proportions of men with minimally important differences (MIDs) in each domain were tested using repeated measures logistic models with prespecified thresholds. Results: The 3-year incidence of grade ≥1 (9.2% vs 2.0%; P=.028) and grade ≥2 (5.7% vs 0%; P=.012) rectal toxicity favored the spacer arm. Grade ≥1 urinary incontinence was also lower in the spacer arm (15% vs 4%; P=.046), with no difference in grade ≥2 urinary toxicity (7% vs 7%; P=0.7). From 6 months onward, bowel QOL consistently favored the spacer group (P=.002), with the difference at 3 years (5.8 points; P<.05) meeting the threshold for a MID. The control group had a 3.9-point greater decline in urinary QOL compared with the spacer group at 3 years (P<.05), but the difference did not meet the MID threshold. At 3 years, more men in the control group than in the spacer group had experienced a MID decline in bowel QOL (41% vs 14%; P=.002) and urinary QOL (30% vs 17%; P=.04). Furthermore, the control group were also more likely to have experienced large declines (twice the MID) in bowel QOL (21% vs 5%; P=.02) and urinary QOL (23% vs 8%; P=.02). Conclusions: The benefit of a hydrogel spacer in reducing the rectal dose, toxicity, and QOL declines after image guided intensity modulated radiation therapy for prostate cancer was maintained or increased with a longer follow-up period, providing stronger evidence for the benefit of hydrogel spacer use in prostate radiation therapy.

• OSTI ID: 22649887
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 97, Issue 5; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
GY RANGE 10-100
HYDROGELS
MEN
NEOPLASMS
PROSTATE
RADIOTHERAPY
RECTUM
TOXICITY