Background and purpose: We sought to analyze the effect of polyethylene glycol (PEG) hydrogel on rectal doses in prostate cancer patients undergoing radiotherapy.
Materials and methods: Between July 2009 and April 2013, we treated 200 clinically localized prostate cancer patients with high-dose rate (HDR) brachytherapy±intensity modulated radiation therapy. Half of the patients received a transrectal ultrasound (TRUS)-guided transperineal injection of 10mL PEG hydrogel (DuraSeal™ Spinal Sealant System; Covidien, Mansfield, MA) in their anterior perirectal fat immediately prior to the first HDR brachytherapy treatment and 5mL PEG hydrogel prior to the second HDR brachytherapy treatment. Prostate, rectal, and bladder doses and prostate-rectal distances were calculated based upon treatment planning CT scans.
Results: There was a success rate of 100% (100/100) with PEG hydrogel implantation. PEG hydrogel significantly increased the prostate-rectal separation (mean±SD, 12±4mm with gel vs. 4±2mm without gel, p<0.001) and significantly decreased the mean rectal D2 mL (47±9% with gel vs. 60±8% without gel, p<0.001). Gel decreased rectal doses regardless of body mass index (BMI).
Conclusions: PEG hydrogel temporarily displaced the rectum away from the prostate by an average of 12mm and led to a significant reduction in rectal radiation doses, regardless of BMI.
Keywords: Gel; HDR; High-dose-rate; Prostate; Radiotherapy.
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