Who Benefits From a Prostate Rectal Spacer? Secondary Analysis of a Phase III Trial.

Autor:	Quinn TJ; The Department of Radiation Oncology, Beaumont Hospital, Dearborn, Michigan., Daignault-Newton S; Department of Biostatistics, University of Michigan, Ann Arbor, Michigan., Bosch W; Washington University School of Medicine, St. Louis, Missouri., Mariados N; Associated Medical Professionals of NY PLLC, Syracuse, New York., Sylvester J; 21st Century Oncology, Inc, Lakewood Ranch, East Bradenton, Florida., Shah D; Western New York Urology Associates, LLC, D/B/A Cancer Care of WNY, Cheektowaga, New York., Gross E; The Urology Center of Colorado, Denver, Colorado., Hudes R; Chesapeake Urology Associates Chesapeake Urology Research Associates (The Prostate Center), Owings Mills, Maryland., Beyer D; Cancer Centers of Northern Arizona, Sedona Arizona., Kurtzman S; Urological Surgeons of Northern California, Inc, Campbell, California., Bogart J; The Research Foundation of State University of New York, SUNY Upstate Medical University, Syracuse, New York., Hsi RA; Peninsula Cancer Center, Poulsbo, Washington., Kos M; Northern Nevada Radiation Oncology, Reno, Nevada., Ellis R; Penn State University School of Medicine, Hershey, Pennsylvania., Logsdon M; Sutter Health Sacramento Sierra Region Sutter Institute for Medical Research, Sacramento, California., Zimberg S; Advanced Radiation Centers of New York, Lake Success, New York., Forsythe K; Oregon Urology Institute, Springfield, Oregon., Zhang H; University of Rochester, Rochester, New York., Soffen E; CentraState Medical Center, Freehold, New Jersey., Francke P; Carolina Regional Cancer Center, LLC/21st Century Oncology, Inc, Myrtle Beach, South Carolina., Mantz C; 21st Century Oncology, Inc, Fort Meyers, Florida., DeWeese T; The Johns Hopkins University, Baltimore, Maryland., Gay HA; Washington University School of Medicine, St. Louis, Missouri., Michalski J; Washington University School of Medicine, St. Louis, Missouri., Hamstra DA; The Department of Radiation Oncology, Beaumont Hospital, Dearborn, Michigan. Electronic address: Daniel.Hamstra@Beaumont.org.
Jazyk:	angličtina
Zdroj:	Practical radiation oncology [Pract Radiat Oncol] 2020 May - Jun; Vol. 10 (3), pp. 186-194. Date of Electronic Publication: 2020 Jan 21.
DOI:	10.1016/j.prro.2019.12.011
Abstrakt:	Purpose: Previously a phase III trial of a hydrogel rectal spacer during prostate radiation therapy found decreased toxicity and a clinically significant improvement in bowel quality of life (QOL) at 3 years by the Expanded Prostate Cancer Index. We performed a secondary analysis to identify men less likely to benefit. Methods and Materials: Clinical and dosimetric data for the 222 patients enrolled on the SpaceOAR phase III trial were analyzed. The volume of rectum treated to 70 Gy (V70) and the quantitative analysis of normal tissue effects in the clinic (QUANTEC) rectal dose goals were used as surrogates for clinical benefit and plan quality. Mean bowel QOL was assessed at 15 and 36 months posttreatment and the likelihood of 1× (5 points) or 2× (10 points) minimally important difference changes were assessed. Results: Rectal V70 was correlated with physician scored toxicity (P = .033) and was used as a surrogate for plan quality. There was no correlation between prostate volume and rectal V70 (r = 0.077). Rectal V70 pre- and post-hydrogel was 13% and 3% for the smallest prostates (<40 mL) and 12% and 2% for the largest (>80 mL). The relative reduction in rectal V70 of 78% did not vary by prespacer V70, but the absolute reduction was greater for a higher V70. All spacer plans met the 5 QUANTEC rectal dose constraints, although 92% of control plans met all constraints. At 3 years, those not meeting all QUANTEC goals had a 15.0-point (standard deviation 15.1) decline, control patients meeting QUANTEC goals had a 4.0-point (9.5) decline, and spacer had >0.5 (7.6; P < .01). Previous surgery was not correlated with QOL (P = .8). Across prognostic groups, including age, body mass index, previous surgery, target volume, or quality of radiation plans, there was no statistically significant heterogeneity in the relative benefit of spacer in decreasing the risk of 1× or 2× the minimally important difference declines. Conclusions: There was little heterogeneity in the likelihood of spacer reducing the risk of declines in bowel QOL across clinical and dosimetric variables. Even for the >95% of plans meeting QUANTEC rectal criteria, hydrogel spacer provided potentially meaningful benefits. (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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