High Dose Rate Temporary Seed Implants
High dose rate brachytherapy (HDR) is done in 4 steps. The first step is placement of catheters into and around the prostate. Once the catheters are in position, the two next steps are called “simulation” and “dosimetry.” Simulation involves taking either a CT scan or ultrasound image of the prostate with the catheters in place. Calculations are then made to determine the dosage of radiation. A robotic delivery device controlling a single, tiny, but potent, radioactive seed attached to the end of a fine cable is inserted into each of the hollow catheters to deliver the therapy. Each treatment takes about 15-30 minutes. HDR in combination with intensity modulated radiation (IMRT) produces consistently better cure rates than surgery. A randomized clinical trial from England reported that HDR plus IMRT is better than IMRT alone. HDR can also be used as a standalone form of therapy. HDR monotherapy cure rates are so similar to the cure rates with HDR plus IMRT that it raises the serious question as to whether the addition of IMRT provides any additional benefit.
Side Effects
Temporary urinary side effects are expected to last 1 to 2 weeks then taper off. Prostate swelling or urinary bleeding immediately after the procedure occasionally requires a temporary urinary catheter. Urinary incontinence occurs in less than 1% of cases; stricture occurs in less than 1% of men treated in top-flight centers. The risk of sexual dysfunction is similar to other forms of radiation.
ABOUT THE AUTHOR:
Jeffrey Demanes, MD received his bachelor of arts degree from UC Berkeley and his medical degree from the David Geffen School of Medicine at UCLA. He completed residencies in internal medicine and radiation oncology at UCLA and his medical oncology fellowship at UCSF. He is the past chairman and president of the American College of Radiation Oncology. Dr. Demanes specializes in brachytherapy, the surgical subspecialty of radiation oncology. He founded the California Endo Curietherapy Center (CET) in 1981 and has performed more than 10,000 surgical radiation implants. He is a professor emeritus in the Department of Radiation Therapy at UCLA.