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

Hamstra, Daniel A.; Mariados, Neil; Sylvester, John; Shah, Dhiren; Karsh, Lawrence I.; Hudes, Richard; Beyer, David; Kurtzman, Steven; Bogart, Jeffrey A.; Hsi, R.A.; Kos, Michael; Ellis, Rodney J.; Logsdon, Mark D.; Zimberg, S.H.; Forsythe, Kevin; Zhang, Hong; Soffen, Edward M.; Francke, Patrick; Mantz, C.A.; Rossi, Peter J.; DeWeese, T.L.; Daignault‐Newton, Stephanie; Fischer‐Valuck, Benjamin W.; Chundury, Anupama; Bosch, Walter; Michalski, Jeff M.

doi:10.1016/j.ijrobp.2016.12.024

Cited by 296 publications

(266 citation statements)

References 38 publications

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“…Most experience with hydrogel injection has been in the region between the prostate and rectum for men receiving dose-escalated prostate RT (25-28). Recently reported results of a phase III study of dose-escalated IMRT for prostate cancer in 222 men randomized 2:1, with and without spacer placement, respectively, demonstrated a reduced rectal dose and toxicity and improved quality of life (25). …”

Section: Discussionmentioning

confidence: 99%

“…Although no significant adverse events of spacer injection have been reported to date in the prostateerectum hydrogel spacer (25) nor for TraceIT hydrogel as a tissue marker (30-32), the unique anatomy and technical challenges of spacer placement in the potential space between the pancreas and duodenum could potentially pose new risks. Microscopic analysis of the duodenal mucosa and pancreatic parenchyma after hydrogel injection in our cadaveric specimens revealed a few regions of injection within the muscularis propia of the duodenum.…”

Section: Discussionmentioning

confidence: 99%

“…Previously, hydrogel injection for spacing organs at risk (OARs) from the radiation target to increase the deliverable dose or improve the safety of RT has been evaluated most extensively in the treatment of prostate cancer (25-28), with some experience in gynecologic cancers as well (29). Hydrogel spacer injection between the rectum and prostate and seminal vesicles has resulted in a reduced rectal dose and toxicity and improved quality of life (25).…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogel spacer injection between the rectum and prostate and seminal vesicles has resulted in a reduced rectal dose and toxicity and improved quality of life (25). A smaller report of patients with gynecologic malignancies demonstrated the utility of hydrogel injection in patients requiring repeat irradiation to increase the space between the vagina and rectum to allow for a reduction in the dose delivered to the rectum (29).…”

Section: Introductionmentioning

confidence: 99%

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A Novel Absorbable Radiopaque Hydrogel Spacer to Separate the Head of the Pancreas and Duodenum in Radiation Therapy for Pancreatic Cancer

Rao

Feng

Shin³

et al. 2017

International Journal of Radiation Oncology*Biology*Physics

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Summary We have demonstrated the feasibility of an endoscopic ultrasound-guided injectable hydrogel separation technique using a cadaveric model to increase the space between the head of the pancreas and duodenum. Using modeling studies, we identified the minimum distance of this separation for optimal sparing of the duodenum, setting the foundation for future clinical trials using this technique to enable dose escalation with either stereotactic or intensity-modulated radiation therapy for patients with unresectable pancreatic cancer. Purpose We assessed the feasibility and theoretical dosimetric advantages of an injectable hydrogel to increase the space between the head of the pancreas (HOP) and duodenum in a human cadaveric model. Methods and Materials Using 3 human cadaveric specimens, an absorbable radiopaque hydrogel was injected between the HOP and duodenum by way of open laparotomy in 1 case and endoscopic ultrasound (EUS) guidance in 2 cases. The cadavers were subsequently imaged using computed tomography and dissected for histologic confirmation of hydrogel placement. The duodenal dose reduction and planning target volume (PTV) coverage were characterized using pre- and postspacer injection stereotactic body radiation therapy (SBRT) plans for the 2 cadavers with EUS-guided placement, the delivery method that appeared the most clinically desirable. Modeling studies were performed using 60 SBRT plans consisting of 10 previously treated patients with unresectable pancreatic cancer, each with 6 different HOP–duodenum separation distances. The duodenal volume receiving 15 Gy (V15), 20 Gy (V20), and 33 Gy (V33) was assessed for each iteration. Results In the 3 cadaveric studies, an average of 0.9 cm, 1.1 cm, and 0.9 cm HOP–duodenum separation was achieved. In the 2 EUS cases, the V20 decreased from 3.86 cm3 to 0.36 cm3 and 3.75 cm3 to 1.08 cm3 (treatment constraint <3 cm3), and the V15 decreased from 7.07 cm3 to 2.02 cm3 and 9.12 cm3 to 3.91 cm3 (treatment constraint <9 cm3). The PTV coverage improved or was comparable between the pre- and postinjection studies. Modeling studies demonstrated that a separation of 8 mm was sufficient to consistently reduce the V15, V20, and V33 to acceptable clinical constraints. Conclusions Currently, dose escalation has been limited owing to radiosensitive structures adjacent to the pancreas. We demonstrated the feasibility of hydrogel separation of the HOP and duodenum. Future studies will evaluate the safety and efficacy of this technique with the potential for more effective dose escalation using SBRT or intensity-modulated radiation therapy to improve the outcomes in patients with unresectable pancreatic cancer.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Novel Absorbable Radiopaque Hydrogel Spacer to Separate the Head of the Pancreas and Duodenum in Radiation Therapy for Pancreatic Cancer

Rao

Feng

Shin³

et al. 2017

International Journal of Radiation Oncology*Biology*Physics

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“…Moreover, likely clinically unjustified considering only 6% of the control arm experienced grade 2 or greater gastrointestinal toxicity (only one case [1.3%] of grade 3) in the SpaceOAR pivotal randomized study. 6 Therefore, clinical feasibility and performance data in the Canadian setting will allow economic modeling accounting for the costs of rectal spacer, repeated planning imaging studies, shorter versus longer treatment duration, and associated toxicities over the full cycle of care.…”

Section: Discussionmentioning

confidence: 99%

Use of hydrogel spacer for improved rectal dose-sparing in patients undergoing radical radiotherapy for localized prostate cancer: First Canadian experience

Berlin

Tomasso

Ballantyne

et al. 2017

CUAJ

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We describe the initial experience using a hydrogel spacer (SpaceOAR) to separate the prostaterectum interspace in patients planned to undergo radical hypofractionated image-guided intensity-modulated radiotherapy (IG-IMRT). We depict and discuss the impact of SpaceOAR in the context of hypofractionated IG-IMRT, and the particular considerations for its applications in the Canadian setting. CUAJ -Research LetterBerlin et al: Hydrogel spacer for dose-sparing in prostate cancer patients Introduction Prostate cancer (PCa) is the most common non-cutaneous malignancy in Canadian men.

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Association of the Placement of a Perirectal Hydrogel Spacer With the Clinical Outcomes of Men Receiving Radiotherapy for Prostate Cancer

et al. 2020

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IMPORTANCE Perirectal spacers are intended to lower the risk of rectal toxic effects associated with prostate radiotherapy. A quantitative synthesis of typical clinical results with specific perirectal spacers is limited. OBJECTIVE To evaluate the association between perirectal hydrogel spacer placement and clinical outcomes of men receiving radiotherapy for prostate cancer. DATA SOURCES A systematic search was performed of the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for articles published through September 2019.STUDY SELECTION Studies comparing men who received a hydrogel spacer vs men who did not receive a spacer (controls) prior to prostate radiotherapy. DATA EXTRACTION AND SYNTHESISVia random-effects meta-analysis, group comparisons were reported using the weighted mean difference for continuous measures and the risk ratio for binary measures. MAIN OUTCOMES AND MEASURESProcedural results, the percentage volume of rectum receiving at least 70 Gy radiation (v70), early (Յ3 months) and late (>3 months) rectal toxic effects, and early and late changes in bowel-related quality of life on the Expanded Prostate Cancer Index Composite (minimal clinically important difference, 4 points). RESULTSThe review included 7 studies (1 randomized clinical trial and 6 cohort studies) involving 1011 men (486 who received a hydrogel spacer and 525 controls), with a median duration of patient follow-up of 26 months (range, 3-63 months). The success rate of hydrogel spacer placement was 97.0% (95% CI, 94.4%-98.8% [5 studies]), and the weighted mean perirectal separation distance was 11.2 mm (95% CI, 10.1-12.3 mm [5 studies]). Procedural complications were mild and transient, occurring in 0% to 10% of patients within the studies. The hydrogel spacer group received 66% less v70 rectal irradiation compared with controls (3.5% vs 10.4%; mean difference, −6.5%; 95% CI, -10.5% to -2.5%; P = .001 [6 studies]). The risk of grade 2 or higher rectal toxic effects was comparable between groups in early follow-up (4.5% in hydrogel spacer group vs 4.1% in control group; risk ratio, 0.82; 95% CI, 0.52-1.28; P = .38 [6 studies]) but was 77% lower in the hydrogel spacer group in late follow-up (1.5% vs 5.7%; risk ratio, 0.23; 95% CI, 0.06-0.99; P = .05 [4 studies]).Changes in bowel-related quality of life were comparable between groups in early follow-up (mean difference, 0.2; 95% CI, -3.1 to 3.4; P = .92 [2 studies]) but were greater in the hydrogel spacer group in late follow-up (mean difference, 5.4; 95% CI, 2.8-8.0; P < .001 [2 studies]).

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

Cited by 296 publications

References 38 publications

A Novel Absorbable Radiopaque Hydrogel Spacer to Separate the Head of the Pancreas and Duodenum in Radiation Therapy for Pancreatic Cancer

A Novel Absorbable Radiopaque Hydrogel Spacer to Separate the Head of the Pancreas and Duodenum in Radiation Therapy for Pancreatic Cancer

Use of hydrogel spacer for improved rectal dose-sparing in patients undergoing radical radiotherapy for localized prostate cancer: First Canadian experience

Association of the Placement of a Perirectal Hydrogel Spacer With the Clinical Outcomes of Men Receiving Radiotherapy for Prostate Cancer

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