Protection of Rectum From High Radiation Doses

The purpose of this study is to evaluate the usefulness of diluted DuraSeal product as a spacer between prostate and rectum in prostate cancer low dose brachytherapy.

Radiation therapy for prostate cancer leads to inappropriate radiation dose to the rectum wall leading rectum adverse effects in long term for some patients. A resorbable spaces between prostate and rectum could decrease the incidence of these side effect. In this trial, men with prostate cancer with intention to curative treatment by low dose brachytherapy will be recruited. Diluted DuraSeal will be applied between rectum and prostate at the end of the brachytherapy seed implantation procedure. After the implantation of the brachytherapy seeds, a needle is placed between rectum and prostate through perineal skin under transrectal ultrasound guidance. The proper position of the needle is confirmed by the injection of 10-15 ml sterile saline solution. After that, DuraSeal components are diluted in 1:1 with sterile saline and 6-10 ml of this diluted product will be injected using DuraSeal applicator. The resolution of the spacer will be followed by repeated plain computer tomography (CT) of pelvis performed a day before operation, a day after the operation, 4 weeks after the operation and 8 weeks after the operation. In addition, magnetic resonance imaging of pelvis performed 8 to 16 weeks after the operation. The space created between prostate and rectum will be documented by plain CT and magnetic resonance imaging. Rectum radiation dose will be calculated based on these scans. Time to DuraSeal resolution will be evaluated from the scans. Possible side effects will be collected by subject interviews during follow-up visits at 4, 8 and 12 weeks after the operation.

Single dose of DuraSeal product with DuraSeal components diluted 1:1 in sterile saline injected between rectum and prostate

Time to spacer resolution will be measured based on the distance between rectum wall and prostate on CT scans before operation and on defined time frame. In addition, magnetic resonance imaging of pelvis will be performed 8 to 16 weeks after the operation in order to confirm the extent of spacer. Spacer volume half life is reported.

Possible side effects will be collected by subject interview and physical examination on specified time frame.

Inclusion Criteria: prostate cancer patients with planned low dose brachytherapy for the treatment of prostate cancer Exclusion Criteria: not willing to participate this study

Heikkila VP, Karna A, Vaarala MH. DuraSeal as a spacer to reduce rectal doses in low-dose rate brachytherapy for prostate cancer. Radiother Oncol. 2014 Aug;112(2):233-6. doi: 10.1016/j.radonc.2014.08.012. Epub 2014 Sep 4.