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

Abstract

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. Sources of support: This work was supported by research funding from Augmenix, Inc, which is now a wholly owned subsidiary of Boston Scientific. Disclosures: N. Mariados and D. Shah have each made small investments in Augmenix. D.A. Hamstra, J. Michalski, and S. Daignault-Newton have provided paid consulting services for Augmenix and Boston Scientific. J. Michalski, H.A. Gay, and W. Bosch have provided core laboratory services for Augmenix.

Long‐term follow‐up after radiotherapy for prostate cancer with and without rectal hydrogel spacer: a pooled prospective evaluation of bowel‐associated quality of life

“…Furthermore, no patients were found on subset analysis whom did not benefit from rectal separation with regards to rectal QOL. Prostate volume, pre‐rectal gel placement dosimetry, distance of rectal separation, geometry of placement, and prior pelvic and/or abdominal surgery did not impact QOL in previous analyses [6,7]. All patients had such a significant decline in rectal dose receiving 70 Gy that all patients benefited from the spacer placement with relative declines of >70% across all patients.…”

Expanding the Utilization of Rectal Spacer Hydrogel for Larger Prostate Glands (>80 cc): Feasibility and Dosimetric Outcomes

“…In our experience, hydrogel placement is feasible in large glands >80 cm 3 , even when including a subgroup of patients with prostates >100 cm 3 (100.1-186.6 cm 3 ) with very favorable dosimetric outcomes which are in line with benchmark published results with smaller glands. 11 , 34 …”

“…Of note, a secondary analysis of this trial described a small subset of patients with prostate glands between 80-100 cc with the post-spacer rV70 of 2%, reduced from 12% in the comparison prespacer scans. [34] The authors concluded that regardless of prostatic volume, there was consistent relative reduction in rectal V70 following spacer placement between 70-84%.…”

Successful Use of Absorbable Hydrogel Rectal Spacers (SpaceOAR) Before Salvage Radiation Therapy After Previous Prostate Cryotherapy

“…Presumably for this reason, some physicians have expressed concerns about whether absorbable hydrogel spacers could be safely and effectively deployed in patients who have been previously treated with cryosurgery. 13,14 Herein we present the first reported cases where absorbable hydrogel spacers were successfully used following previous prostate cryotherapy.…”

“…Some authors have raised concerns that previous prostate cancer treatment (e.g., cryotherapy, high-intensity focused ultrasound) may prevent successful dissection of this space, resulting in suboptimal spacer placement or procedural complication. 13,13 However, previous reports have described successful use of hydrogel spacers following previous prostatectomy, external-beam radiation therapy, and high-intensity focused ultrasound. 7,18,25 In this report, we have shown that absorbable hydrogel spacers can also be effectively used in patients previously treated with prostate cryoablation, without periprocedural complication.…”