Extracapsular Prostate Brachytherapy Using Iodine-125 for Intermediate and Selected High-Risk Prostate Cancer: Technical Notes

Abstract

Abstract Introduction: Our aim is to describe extracapsular prostate brachytherapy (ECPB) techniques using low-dose-rate (LDR) for patients with intermediate-risk prostate cancer (IRPC) and selected high-risk prostate cancer (HRPC). Materials and Methods: Using stranded iodine-125 seeds, dose can be extended to the capsule and seminal vesicles (SVs). Intraoperative use of fluoroscopy with a cystogram can increase the extracapsular dose at the base and proximal SV compared with using ultrasound alone, with a seed source at the tip of each needle to push the dose cephalad. Visualization of the prostate base can be improved with a urinary catheter, with additional seeds placed posterior to the catheter balloon, along with additional stranded sources placed into the SV. For apical disease, a needle tip can be placed at the apex of the prostate under ultrasound guidance, and a fluoroscopic image can be referenced during the case, to ensure seed placement below the prostate apex. A peripheral loading technique is applied so that there is at least 3 mm coverage beyond the prostate radially, while additional seeds are inserted into areas of gross disease. Results: Our prior published experience of IRPC and selected HRPC showed excellent freedom from biochemical failure with 10-year follow-up. Our ECPB approach requires the use of more seeds (P < .0001), compared with a standard prostate brachytherapy approach, while requiring the use of fluoroscopy in addition to ultrasound. Conclusion: LDR prostate brachytherapy using iodine-125 alone with extracapsular techniques is a reasonable treatment option for IRPC and selected HRPC, but unfortunately is becoming a lost art.