BERKELEY, CA (UroToday.com) - Radiotherapy is commonly used therapy for prostate cancer. To achieve the best result in radiotherapy, the prostate needs to receive a sufficiently high absorbed dose. High prostate dose, however, leads to some level of undesired doses to the rectum, bladder and urethra. Side effects may emerge even years after treatment.
Several spacer techniques have been introduced to reduce rectum doses during external beam radiation therapy and brachytherapy. We evaluated the utility of off-label use of DuraSeal® polyethylene glycol (PEG) gel in low-dose (LDR) prostate brachytherapy seed implantation to reduce rectum doses. Ten consecutive patients treated with I-125 seed implantation for prostate cancer were injected with diluted DuraSeal® between the prostate and rectum after seed implantation. The injected volume was approximately 10 ml. Gel clearance rates and rectum doses (D2cc, maximum dose that covers 2 cm3) were measured and calculated from transrectal ultrasound, computer tomography, and magnetic resonance imaging follow-up images (a day after injection and 1–4 months after injection) with and without a clearance effect. The mean dose reduction in rectal D2cc when using I-125 was 31+/-13 Gy with no clearance effect, and 22+/-12 Gy with a gel clearance effect. Gel clearance half-life, measured as the separation between prostate and rectum, was 110 days, and gel volume half-life was 47 days. The magnitude of postoperative prostate edema was also measured from the follow-up images. Edema half-life was measured as 27 days.
Diluted DuraSeal® was easy to use and, in spite of a clearance effect, useful in decreasing D2cc rectal doses in LDR prostate brachytherapy treatments. Further, it may also be beneficial for the reduction of rectum doses with external beam radiation therapy.
Markku H. Vaarala as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Finland