A device designed to increase the space between the prostate and the rectum in prostate cancer patients undergoing radiation therapy has the potential to significantly reduce rectal injury, according to results of an international, prospective, phase I clinical trial. Rectal injury is a side effect caused by unwanted radiation exposure that can leave men with compromised bowel function following treatment.
The device, known as the BioProtect Balloon Implant, was tested on 27 patients with localized prostate cancer. The device is designed to reduce radiation exposure to the rectum by expanding the space between the rectum and the prostate. It remains in place throughout the treatment process, and it is designed to biodegrade completely within 6 months.
“We found that the addition of BioProtect reduced the radiation dose delivered to the rectum by an average of about 30%,” said primary investigator Mitchell Anscher, MD, of Virginia Commonwealth University Massey Cancer Center in Richmond. “Most notable was the device’s ability to reduce exposure at higher radiation levels, which indicates that the cancer could be safely treated with more aggressive protocols.”
The researchers observed a greater reduction in radiation exposure to the rectum as radiation dose levels were increased. At 50% of prescribed dose, little difference in rectal tissue exposure was seen. However, a 55.3% reduction was noted at 70% of the prescribed dosage, a 64% reduction at 80% of the prescribed dosage, a 72% reduction at 90% of the prescribed dosage, and an 82.3% reduction at 100% of the prescribed dosage. Results of this study were published in the Journal of Radiation Oncology (2013;106(2):210-214).
As anticipated, all of the implanted balloons started to degrade 3 months after implantation. The researchers concluded that the device could be especially useful in hypofractionated radiation therapy. Hypofractionated radiation therapy uses larger doses of radiation applied over a shorter number of treatments instead of delivering a small percentage of the total dose during daily treatments spread over a longer period of time.
“Massey has many patients that travel from rural areas for care. If this device allows us to deliver the prescribed radiation dose over a shorter period of time, we can reduce the overall burden on the patient, and they can spend less time away from work and their family,” said Anscher. “We hope to initiate a phase II clinical trial in a larger cohort of patients in order to determine the effectiveness of the device in reducing rectal injury in comparison to standard treatment protocols.”