Absorbable Hydrogel Spacer Use in Prostate Radiotherapy: A Comprehensive Review of Phase 3 Clinical Trial Published Data

Karsh, Lawrence I.; Gross, Eric; Pieczonka, Christopher; Aliotta, Philip J.; Skomra, Christopher J.; Ponsky, Lee; Nieh, Peter T.; Han, Misop; Hamstra, Daniel A.; Shore, Neal D.

doi:10.1016/j.urology.2017.11.016

Cited by 84 publications

(89 citation statements)

References 29 publications

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“…Prostate-rectum separation achieved leads to improving dosimetric rectal profiles even with a minimal prostateerectum separation rectal doses can significantly reduce because of the rapid dose fall off with BT. These results are consistent with other EBRT-specific reports (10,13). Of the 615 patients, there were 26 patients that the placement of hydrogel spacer was not successful because of technically failures during implantation such as insufficient hydrodissection, and injection of hydrogel into the rectal lumen (25,28).…”

Section: Discussionsupporting

confidence: 89%

“…As a consequence, the application of rectal displacement devices resulted in a decrease of acute and late rectal toxicity from EBRT (9e16). Randomized studies demonstrated the clinical benefit of PEG hydrogel spacer in terms of acute and late rectal toxicities during prostate EBRT (10). Recently, several studies have been investigated the role of PEG hydrogel spacers during prostate BT in the different setting.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of prostate brachytherapy techniques with polyethylene glycol–based hydrogel spacers: A systematic review

Ardekani

Ghaffari

2020

Brachytherapy

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The objective of this overview was to critically evaluate the effect of polyethylene glycol (PEG)-based hydrogel spacers during prostate brachytherapy with regard to dosimetric and clinical benefits, as well as procedure-related toxicity. METHODS AND MATERIALS: A systematic search in the PubMed database was performed. RESULTS: A total of 12 studies, involving 615 patients with PEG hydrogel injection, were included. Overall, patients well tolerated the implantation of PEG hydrogel spacers with an excellent safety profile. However, although there were some procedure-related complications, rates of these complications were very rare. Toxicities related to the spacer were limited to Grade 1 rectal discomfort and pain (9/615 patients), Grade 2 rectal ulceration (1 in 615 patients), perineal abscess (1 in 615 patients), and bacterial prostatitis (2/615 patients) according to Common Terminology Criteria for Adverse Events v4.0 grading scheme. The application of PEG hydrogel spacers significantly reduced radiation doses to the rectum during prostate brachytherapy in the different setting. Although there was no prospective randomized clinical trial, retrospective studies showed that reducing rectal doses by the implantation of PEG hydrogel may result in an improvement in rectal toxicity. CONCLUSIONS: The insertion of hydrogel spacers is safe, resulting in a significant decrease in rectal doses. This may lead to a reduction in rectal or gastrointestinal toxicity. Prospective randomized clinical trials are warranted to confirm the clinical impact of rectal dosimetric improvements.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Optimization of prostate brachytherapy techniques with polyethylene glycol–based hydrogel spacers: A systematic review

Ardekani

Ghaffari

2020

Brachytherapy

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“…[12] Several studies report the feasibility of hydrogel rectal spacers in patients receiving primary radiation for prostate cancer. [13][14][15][16][17][18] A recent UC patient case report demonstrated the successful treatment with Ir-192 brachytherapy for primary PC, after SpaceOAR gel injection. The patient reported no bowel issues following HDR brachytherapy after one day, one week and five months, respectively.…”

Section: Discussionmentioning

confidence: 99%

Hydrogel Spacer may Allow Prostate Re-irradiation even in Patients with Ulcerative Colitis: A Case Report

et al. 2020

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Salvage radiotherapy is a valid option for locally recurrent prostate cancer (PC) patients. Two of the treatment options are as follows: interventional radiotherapy or stereotactic body radiotherapy (SBRT). SBRT has the main advantage as a noninvasive procedure. Synthetic gel injection into the prostate and rectum space, as a novel technique in prostate radiotherapy, spares the anterior rectal wall from a high dose. Inflammatory bowel disease, including Crohn's disease and ulcerative colitis (UC), contraindicate external beam radiotherapy due to increased bowel complication risk. In this study, we describe the first PC patient with UC in remission treated with salvage SBRT and hydrogel rectal spacer. After ten months of follow-up, no bowel symptoms were reported, and SBRT provided both biochemical and clinical response. Even patients with UC and radio-recurrent PC may be viable salvage SBRT candidates.

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“…Rectal sparing devices such as hydrogel spacers offer the prospect of increased space between the prostate and rectum, causing reduced rectal dose and potentially reduced injury. [3][4][5][6][7] However, there are drawbacks to offering an RSD to all patients. With an invasive procedure such as transperineal hydrogel insertion there are inherent adverse risks to the patient such as rectal infiltration, rectal ulceration, and infection, although reportedly low so far.…”

Section: Introductionmentioning

confidence: 99%

Comparison of statistical machine learning models for rectal protocol compliance in prostate external beam radiation therapy

et al. 2020

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Purpose: Limiting the dose to the rectum can be one of the most challenging aspects of creating a dosimetric external beam radiation therapy (EBRT) plan for prostate cancer treatment. Rectal sparing devices such as hydrogel spacers offer the prospect of increased space between the prostate and rectum, causing reduced rectal dose and potentially reduced injury. This study sought to help identify patients at higher risk of developing rectal injury based on estimated rectal dosimetry compliance prior to the EBRT simulation and planning procedure. Three statistical machine learning methods were compared for their ability to predict rectal dose outcomes with varied classification thresholds applied. Methods: Prostate cancer patients treated with conventionally fractionated EBRT to a reference dose of 74-78 Gy were invited to participate in the study. The dose volume histogram data from each dosimetric plan was used to quantify planned rectal volume receiving 50%, 83% 96%, and 102% of the reference dose. Patients were classified into two groups for each of these dose levels: either meeting tolerance by having a rectal volume less than a clinically acceptable threshold for the dose level (Y) or violating the tolerance by having a rectal volume greater than the threshold for the dose level (N). Logistic regression, classification and regression tree, and random forest models were compared for their ability to discriminate between class outcomes. Performance metrics included area under the receiver operator characteristic curve (AUC), sensitivity, specificity, positive predictive value and negative predictive value. Finally, three classification threshold levels were evaluated for their impact on model performance. Results: A total of 176 eligible participants were recruited. Variable importance differed between model methods. Area under the receiver operator characteristic curve performance varied greatly across the different rectal dose levels and between models. Logistic regression performed best at the 83% reference dose level with an AUC value of 0.844, while random forest demonstrated best discrimination at the 96% reference dose level with an AUC value of 0.733. In addition to the standard classification probability threshold of 50%, the clinically representative threshold of 10%, and the best threshold from each AUC plot was applied to compare metrics. This showed that using a 50% threshold and the best threshold from the AUC plots yields similar results. Conversely, applying the more conservative clinical threshold of 10% maximized the sensitivity at V83_RD and V96_RD for all model types. Based on the combination of the metrics, logistic regression would be the recommendation for rectal protocol compliance prediction at the 83% reference dose level, and random forest for the 96% reference dose level, particularly when using the clinical probability threshold of 10%. Conclusions: This study demonstrated the efficacy of statistical machine learning models on rectal protocol compliance prediction for prostate cancer...

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Absorbable Hydrogel Spacer Use in Prostate Radiotherapy: A Comprehensive Review of Phase 3 Clinical Trial Published Data

Cited by 84 publications

References 29 publications

Optimization of prostate brachytherapy techniques with polyethylene glycol–based hydrogel spacers: A systematic review

Optimization of prostate brachytherapy techniques with polyethylene glycol–based hydrogel spacers: A systematic review

Hydrogel Spacer may Allow Prostate Re-irradiation even in Patients with Ulcerative Colitis: A Case Report

Comparison of statistical machine learning models for rectal protocol compliance in prostate external beam radiation therapy

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