Human Collagen Injections to Reduce Rectal Dose During Radiotherapy

Noyes, William; Hosford, Charles C.; Schultz, Steven

doi:10.1016/j.ijrobp.2011.02.034

Cited by 105 publications

(86 citation statements)

References 19 publications

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“…Various techniques to decrease the rectal dose have been introduced, such as spacer gels and endorectal balloons [11][12][13][14][15]. The spacer gel is injected between the prostate gland and the anterior rectal wall, which increases the distance in between, resulting in significantly decreased dose to the rectal wall [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…The spacer gel is injected between the prostate gland and the anterior rectal wall, which increases the distance in between, resulting in significantly decreased dose to the rectal wall [11][12][13]. The endorectal balloon is placed in the rectum and inflated with air to expand the rectum [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…The anterior rectal wall moves toward the prostate and displaces it frontally, while the posterior wall remains in its position resulting in an increased distance between the prostate and the posterior wall [14]. Since the rectal balloon reduces variations in rectum filling and immobilises the prostate, the PTV margin can be reduced, which results in a lower dose to the posterior rectal wall [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

Nilsson

Johansson

Montelius

et al. 2014

Journal of Radiotherapy

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Aim. The aim of the study was to examine the dosimetric effect of rectal retraction, using a rectal retractor, by performing a comparative treatment planning study. Material and Methods. Treatment plans using volumetric arc therapy (VMAT) were produced for ten patients both with and without rectal retraction. A hypofractionation scheme of 42.7 Gy in seven fractions was used. The dose to the rectal wall was evaluated for both methods (with and without retraction) using four dose-volume criteria:40.1 Gy , 38.3 Gy , 36.5 Gy , and 32.6 Gy . Results. The retraction of the rectal wall increased the distance between the rectal wall and the prostate. The rectal wall volume was reduced to zero for all dose-volume values except for 32.6 Gy , which was 0.2 cm 3 in average when the rectal retractor was used. Conclusion. There was a significant decrease of 40.1 Gy , 38.3 Gy , 36.5 Gy , and 32.6 Gy when the rectal retractor was used without compromising the dose coverage of planning target volume (PTV).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

Nilsson

Johansson

Montelius

et al. 2014

Journal of Radiotherapy

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“…Clinical reports have described the use of hyaluronic acid (HA) (8)(9) as well as human collagen (10). While promising, issues related to HA radiation sensitivity (11) and the theoretical possibility of infectious agent transmission from human derived products have resulted in considerable interest in synthetic polyethylene glycol (PEG) based materials, which are currently used elsewhere in the body.…”

Section: Discussionmentioning

confidence: 99%

A multi-institutional clinical trial of rectal dose reduction via injected polyethylene-glycol hydrogel during IMRT for prostate cancer: Analysis of dosimetric outcomes.

Song¹,

Herfarth²,

Uhl³

et al. 2013

JCO

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Purpose-To characterize the effect of a prostate-rectum spacer on dose to rectum during external beam radiotherapy for prostate cancer, and to assess for factors correlated with rectal dose reduction.Materials and methods-Fifty-two patients at 4 institutions were enrolled onto a prospective pilot clinical trial. Patients underwent baseline scans, then were injected with perirectal spacing hydrogel and re-scanned. IMRT plans were created on both scans for comparison. Objectives were to establish rates of creation of ≥7.5mm of prostate-rectal separation, and decrease in rectal V70 of ≥25%. Multiple regression analysis was performed to evaluate associations between pre-vs. postinjection changes in rectal V70 and changes in plan conformity, rectal volume, bladder volume, bladder V70, PTV volume, as well as post-injection mid-gland separation, gel volume, gel thickness, length of PTV/gel contact, or gel left-to-right symmetry.Results-Hydrogel resulted in ≥ 7.5mm prostate-rectal separation in 95.8% of patients; 95.7% had decreased rectal V70 of ≥ 25%, with mean reduction of 8.0 Gy. There were no significant differences in pre-and post-injection prostate, PTV, rectal, and bladder volumes. Plan conformities were significantly different pre-vs. post-injection (P = 0.02); plans with worse conformity indexes post-injection compared to pre-injection (n=13) still had improvements in rectal V70. In multiple regression analysis, greater post-injection reduction in V70 was associated with decreased relative post-injection plan conformity (P=0.01). Reductions in V70 did not significantly vary by institution, despite significant inter-institutional variations in plan conformity. There were no significant relationships between reduction in V70 and the other characteristics analyzed. Conflict of Interest NotificationThis work was supported by funding from Augmenix Inc., including provision of research materials (hydrogel), funding for data monitoring support, and research-related travel costs. Drs. Song, DeWeese, and Ford have also received consulting fees from Augmenix Inc. Conclusions-Injection of hydrogel into prostate-rectal interface resulted in dose reductions to rectum for > 90% of patients treated. Rectal sparing was statistically significant across a range of 10-75 Gy, and was demonstrated within the presence of significant inter-institutional variability in plan conformity, target definitions, and injection results. NIH Public Access

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“…A novel concept consisting of the use of a tissue spacer to displace the anterior rectal wall away from the prostate has been shown to be feasible and to remain stable during the course of treatment, with the advantage of significantly decreasing rectal irradiation 10, 11, 12, 13, 14, 15. In a multicenter trial, high dose rectal sparing with hydrogel spacer for patients undergoing IMRT was associated with reduced rectal toxicity severity and improved bowel quality of life scores 16.…”

Section: Introductionmentioning

confidence: 99%

Validation of rectal sparing throughout the course of proton therapy treatment in prostate cancer patients treated with SpaceOAR^®

Hedrick

Fagundes

Case

et al. 2016

J Applied Clin Med Phys

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The purpose of this study was to investigate the consistency of rectal sparing using multiple periodic quality assurance computerized tomography imaging scans (QACT) obtained during the course of proton therapy for patients with prostate cancer treated with a hydrogel spacer. Forty‐one low‐ and intermediate‐risk prostate cancer patients treated with image‐guided proton therapy with rectal spacer hydrogel were analyzed. To assess the reproducibility of rectal sparing with the hydrogel spacer, three to four QACTs were performed for each patient on day 1 and during weeks 1, 3, and 5 of treatment. The treatment plan was calculated on the QACT and the rectum V90%, V75%, V65%, V50%, and V40% were evaluated. For the retrospective analysis, we evaluated each QACT and compared it to the corresponding treatment planning CT (TPCT), to determine the average change in rectum DVH points. We were also interested in how many patients exceeded an upper rectum V90% threshold on a QACT. Finally, we were interested in a correlation between rectum volume and V90%. On each QACT, if the rectum V90% exceeded the upper threshold of 6%, the attending physician was notified and the patient was typically prescribed additional stool softeners or laxatives and reminded of dietary compliance. In all cases of the rectum V90% exceeding the threshold, the patient had increased gas and/or stool, compared to the TPCT. On average, the rectum V90% calculated on the QACT was 0.81% higher than that calculated on the TPCT. The average increase in V75%, V65%, V50%, and V40% on the QACT was 1.38%, 1.59%, 1.87%, and 2.17%, respectively. The rectum V90% was within ± 1% of the treatment planning dose in 71.2% of the QACTs, and within ± 5% in 93.2% of the QACTs. The 6% threshold for rectum V90% was exceeded in 7 out of 144 QACTs (4.8%), identified in 5 of the 41 patients. We evaluated the average rectum V90% across all QACTs for each of these patients, and it was found that the rectum V90% never exceeded 6%. 53% of the QACTs had a rectum volume within 5 cm3 of the TPCT volume, 68% were within 10 cm3. We found that patients who exceeded the threshold on one or more QACTs had a lower TPCT rectal volume than the overall average. By extrapolating patient anatomy from three to four QACT scans, we have shown that the use of hydrogel in conjunction with our patient diet program and use of stool softeners is effective in achieving consistent rectal sparing in patients undergoing proton therapy.

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Human Collagen Injections to Reduce Rectal Dose During Radiotherapy

Cited by 105 publications

References 19 publications

Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

A multi-institutional clinical trial of rectal dose reduction via injected polyethylene-glycol hydrogel during IMRT for prostate cancer: Analysis of dosimetric outcomes.

Validation of rectal sparing throughout the course of proton therapy treatment in prostate cancer patients treated with SpaceOAR^®

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Human Collagen Injections to Reduce Rectal Dose During Radiotherapy

Cited by 105 publications

References 19 publications

Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

A multi-institutional clinical trial of rectal dose reduction via injected polyethylene-glycol hydrogel during IMRT for prostate cancer: Analysis of dosimetric outcomes.

Validation of rectal sparing throughout the course of proton therapy treatment in prostate cancer patients treated with SpaceOAR®

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Validation of rectal sparing throughout the course of proton therapy treatment in prostate cancer patients treated with SpaceOAR^®