Regulatory evaluation of prostate volume implants: Pitfalls of a retrospective assessment

Radiation oncology and medical physicists quality assurance in British Columbia Cancer Agency Provincial Prostate Brachytherapy Program

“…A subsequent chain of events led to U.S. Senate hearings and Congressional involvement, resulting in a review of the PVAMC by the VA's Office of Inspector General (7). These events have raised significant interest in QA for PB programs in North America and appropriate regulatory evaluation of medical events (8). Subsequent review of the PVAMC's services by the U.S. Nuclear Regulatory Commission (NRC) highlighted the need to articulate and communicate the QA procedures in PB programs (7).…”

Definition of medical event is to be based on the total source strength for evaluation of permanent prostate brachytherapy: A report from the American Society for Radiation Oncology

“…This outcome was unfortunately demonstrated in a recent Veterans Affairs Hospital (VAH) audit in which an unacceptable number of permanent prostate implant brachytherapy (97 out of 116 prostate cancer treatment procedures) were deemed as MEs using the existing dose-based ME criterion 12 . However, on reanalysis, 80 of these 97 were actually not considered MEs using an implanted source strength-based metric recommended by the “VAH blue ribbon panel” or the Advisory Committee for the Medical Use of Isotopes and the scientific organizations including ASTRO because many of these apparent MEs were due to prostate volume changes 12 .…”

“…However, on reanalysis, 80 of these 97 were actually not considered MEs using an implanted source strength-based metric recommended by the “VAH blue ribbon panel” or the Advisory Committee for the Medical Use of Isotopes and the scientific organizations including ASTRO because many of these apparent MEs were due to prostate volume changes 12 . It should be noted that the implanted source strength-based ME criteria would still correctly identify the 17 medically unacceptable implants as MEs.…”

Analysis on the Reporting of Medical Events in Permanent Prostate Brachytherapy

“…The arbitrariness is demonstrated in the re-analysis of the 97 MEs (out of 116 implants) from PVAMC showing that 80 of them were actually due to prostate volume changes after the implant procedures; they would not have been considered as MEs if a source strength-based metric was used [5,7]. If the VA experience is any indication, it would be reasonable to expect that most of the implants in Category III and some in Category II would not be classified as MEs under a source strengthbased standard.…”

“…American Society for Radiation Oncology (ASTRO) expressed concerns in its working group report [5], explaining that a dose-based definition of ME could lead to many properly executed prostate seed implants to be spuriously labeled as MEs due to a number of uncertainties in the post-implant analysis. For example, in NRC's inspection of PVAMC, 97 out of 116 implants were identified as MEs using the existing dose-based rules; three to 80 of them would not be classified as MEs if a source strength-based standard was applied [5,7]. In February 2012, ACMUI proposed a source strength-based ME standard to require at least 80% of the intended source strength to be implanted in the treatment site [6].…”