Purpose: The goal of this work is to evaluate the learning curve of starting a new prostate high dose rate (HDR) brachytherapy program using real-time, on-going analysis of the treatment procedure so agile course corrections can be applied.
Methods: Between 2019 and 2021, the first 80 patients received a 15Gy single fraction prostate HDR brachytherapy boost using the Oncentra Prostate intraoperative ultrasound-guided system at our institution. Plan parameters, plan quality metrics, and procedure timing stats (including the preparation, preplan contouring, pre-planning, needle insertion, final contouring, needle reconstruction, final planning, treatment preparation sub-steps) were recorded for each patient in real time. Reports were generated and sent to the physicists and physicians every ~20 patients and areas of improvement were identified and discussed.
Results: The largest improvement was a decrease in the total procedure duration from an average of 420min to 260min (p<0.001) between the first 20 patients to the last 20. The fastest time was 160min. The duration of each individual step continually decreased with time as well, most notably the patient preparation, needle insertion, and needle reconstruction time. A trial (n=15) of not performing a pre-plan unintentionally increased the total duration due to the increased needle insertion, needle reconstruction, and final contouring time and was discontinued. As our needle placement skills improved, the average number of needles was reduced from 19 to 15 (p<0.001) between the first 20 patients to the last 20. Modifying the needle placement techniques also led to slight improvement trends in several of the dosimetric goals including the PTV V100% coverage, PTV V150% hotspot, and rectum V75%.
Conclusion: Intraoperative ultrasound-guided prostate HDR is a very complex procedure that may seem daunting to new adopters, but notable improvements in the timing and plan quality can be made with careful oversight and willingness to continually adapt new strategies.