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Application of an interstitial and biodegradable balloon system for prostate-rectum separation during prostate cancer radiotherapy: a prospective multi-center study.

Gez E, Cytron S, Ben Yosef R, London D, Corn BW, Alani S, Scarzello G, Dal Moro F, Sotti G, Zattoni F, Koziol I, Torre T, Bassignani M, Kalnicki S, Ghavamian R, Blakaj D, Anscher M, Sommerauer M, Jocham D, Melchert C, Huttenlocher S, Kovacs G, Garg M - Radiat Oncol (2013)

Bottom Line: A significant mean reduction in calculated rectal radiation exposure was achieved.The transperineal implantation of the biodegradable balloon in patients scheduled to receive radiotherapy was safe and achieved a significant and constant gap between the prostate and rectum.This separation resulted in an important reduction in the rectal radiation dose.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background and purpose: Rectal toxicity presents a significant limiting factor in prostate radiotherapy regimens. This study evaluated the safety and efficacy of an implantable and biodegradable balloon specifically designed to protect rectal tissue during radiotherapy by increasing the prostate-rectum interspace.

Patients and methods: Balloons were transperineally implanted, under transrectal ultrasound guidance, into the prostate-rectum interspace in 27 patients with localized prostate cancer scheduled to undergo radiotherapy. Patients underwent two simulations for radiotherapy planning--the first simulation before implant, and the second simulation seven days post implant. The balloon position, the dimensions of the prostate, and the distance between the prostate and rectum were evaluated by CT/US examinations 1 week after the implant, weekly during the radiotherapy period, and at 3 and 6 months post implant. Dose-volume histograms of pre and post implantation were compared. Adverse events were recorded throughout the study period.

Results: Four of 27 patients were excluded from the evaluation. One was excluded due to a technical failure during implant, and three patients were excluded because the balloon prematurely deflated. The balloon status was evaluated for the duration of the radiotherapy period in 23 patients. With the balloon implant, the distance between the prostate and rectum increased 10-fold, from a mean 0.22 ± 0.2 cm to 2.47 ± 0.47 cm. During the radiotherapy period the balloon length changed from 4.25 ± 0.49 cm to 3.81 ± 0.84 cm and the balloon height from 1.86 ± 0.24 cm to 1.67 ± 0.22 cm. But the prostate-rectum interspace distance remained constant from beginning to end of radiotherapy: 2.47 ± 0.47 cm and 2.41 ± 0.43 cm, respectively. A significant mean reduction in calculated rectal radiation exposure was achieved. The implant procedure was well tolerated. The adverse events included mild pain at the perineal skin and in the anus. Three patients experienced acute urinary retention which resolved in a few hours following conservative treatment. No infections or thromboembolic events occurred during the implant procedure or during the radiotherapy period.

Conclusion: The transperineal implantation of the biodegradable balloon in patients scheduled to receive radiotherapy was safe and achieved a significant and constant gap between the prostate and rectum. This separation resulted in an important reduction in the rectal radiation dose. A prospective study to evaluate the acute and late rectal toxicity is needed.

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Sagittal view of CT scan, 7 days post balloon implant.
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Figure 2: Sagittal view of CT scan, 7 days post balloon implant.

Mentions: Geometric analysis: The average prostate-rectum distance increased from 0.22 ± 0.2 cm before implant to 2.47 ± 0.47 cm after the implant. The average distance reduced to 2.41 ± 0.43 cm at the end of radiotherapy (statistically non significant). The balloon dimensions 7 days post-implant and at the end of radiotherapy were as follows: width 3.06 ± 0.27 cm and 2.96 ± 0.25 cm (p = 0.03); length 4.25 ± 0.49 cm and 3.81 ± 0.84 cm (p = 0.023); height 1.86 ± 0.24 cm and 1.67 ± 0.22 cm, respectively. Sagittal reconstruction was possible in only 18 of 23 patients. In the remaining 5 patients the reconstruction failed due to the CT scan slice thicknesses that ranged between 2.5 and 10 mm. The three dimensional parameters of the prostate gland before the balloon implant, during radiotherapy period, and at 3 months follow up, did not change significantly (Table 4). Figures 1–2 present axial and sagittal CT scan images demonstrating the location and configuration of the implanted balloon.


Application of an interstitial and biodegradable balloon system for prostate-rectum separation during prostate cancer radiotherapy: a prospective multi-center study.

Gez E, Cytron S, Ben Yosef R, London D, Corn BW, Alani S, Scarzello G, Dal Moro F, Sotti G, Zattoni F, Koziol I, Torre T, Bassignani M, Kalnicki S, Ghavamian R, Blakaj D, Anscher M, Sommerauer M, Jocham D, Melchert C, Huttenlocher S, Kovacs G, Garg M - Radiat Oncol (2013)

Sagittal view of CT scan, 7 days post balloon implant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3643836&req=5

Figure 2: Sagittal view of CT scan, 7 days post balloon implant.
Mentions: Geometric analysis: The average prostate-rectum distance increased from 0.22 ± 0.2 cm before implant to 2.47 ± 0.47 cm after the implant. The average distance reduced to 2.41 ± 0.43 cm at the end of radiotherapy (statistically non significant). The balloon dimensions 7 days post-implant and at the end of radiotherapy were as follows: width 3.06 ± 0.27 cm and 2.96 ± 0.25 cm (p = 0.03); length 4.25 ± 0.49 cm and 3.81 ± 0.84 cm (p = 0.023); height 1.86 ± 0.24 cm and 1.67 ± 0.22 cm, respectively. Sagittal reconstruction was possible in only 18 of 23 patients. In the remaining 5 patients the reconstruction failed due to the CT scan slice thicknesses that ranged between 2.5 and 10 mm. The three dimensional parameters of the prostate gland before the balloon implant, during radiotherapy period, and at 3 months follow up, did not change significantly (Table 4). Figures 1–2 present axial and sagittal CT scan images demonstrating the location and configuration of the implanted balloon.

Bottom Line: A significant mean reduction in calculated rectal radiation exposure was achieved.The transperineal implantation of the biodegradable balloon in patients scheduled to receive radiotherapy was safe and achieved a significant and constant gap between the prostate and rectum.This separation resulted in an important reduction in the rectal radiation dose.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background and purpose: Rectal toxicity presents a significant limiting factor in prostate radiotherapy regimens. This study evaluated the safety and efficacy of an implantable and biodegradable balloon specifically designed to protect rectal tissue during radiotherapy by increasing the prostate-rectum interspace.

Patients and methods: Balloons were transperineally implanted, under transrectal ultrasound guidance, into the prostate-rectum interspace in 27 patients with localized prostate cancer scheduled to undergo radiotherapy. Patients underwent two simulations for radiotherapy planning--the first simulation before implant, and the second simulation seven days post implant. The balloon position, the dimensions of the prostate, and the distance between the prostate and rectum were evaluated by CT/US examinations 1 week after the implant, weekly during the radiotherapy period, and at 3 and 6 months post implant. Dose-volume histograms of pre and post implantation were compared. Adverse events were recorded throughout the study period.

Results: Four of 27 patients were excluded from the evaluation. One was excluded due to a technical failure during implant, and three patients were excluded because the balloon prematurely deflated. The balloon status was evaluated for the duration of the radiotherapy period in 23 patients. With the balloon implant, the distance between the prostate and rectum increased 10-fold, from a mean 0.22 ± 0.2 cm to 2.47 ± 0.47 cm. During the radiotherapy period the balloon length changed from 4.25 ± 0.49 cm to 3.81 ± 0.84 cm and the balloon height from 1.86 ± 0.24 cm to 1.67 ± 0.22 cm. But the prostate-rectum interspace distance remained constant from beginning to end of radiotherapy: 2.47 ± 0.47 cm and 2.41 ± 0.43 cm, respectively. A significant mean reduction in calculated rectal radiation exposure was achieved. The implant procedure was well tolerated. The adverse events included mild pain at the perineal skin and in the anus. Three patients experienced acute urinary retention which resolved in a few hours following conservative treatment. No infections or thromboembolic events occurred during the implant procedure or during the radiotherapy period.

Conclusion: The transperineal implantation of the biodegradable balloon in patients scheduled to receive radiotherapy was safe and achieved a significant and constant gap between the prostate and rectum. This separation resulted in an important reduction in the rectal radiation dose. A prospective study to evaluate the acute and late rectal toxicity is needed.

Show MeSH
Related in: MedlinePlus