Patient Safety and Medical Event Criteria for Prostate Brachytherapy

In its ongoing efforts to improve the safety and effectiveness of radiation therapy, the American Society for Radiation Oncology (ASTRO) has enhanced its patient safety and quality projects and developed an action plan called Target Safely. A culture of safety and quality control is woven into the fabric of our field, with checks and balances at every level to ensure that the safest and most effective care is delivered to our patients.
The discussion will begin with the basic tenants of the Target Safely campaign followed by a discussion of a specific ASTRO initiative that lies at the intersection of the clinical process of healthcare quality and the regulatory mandate to safeguard the health and safety of radiation therapy patients: ASTRO’s Working Group recommendation on Medical Event (ME) Definition for Permanent Prostate Seed Brachytherapy (In Press, Practical Radiation Oncology). The main goal of the ME criterion is to capture implants of safety and quality assurance significance. A useful ME definition should (a) be assessable by a straightforward and objective criterion that (b) selects only implants with discrepancies between delivered and intended dose that have the potential to cause harm that (c) result from avoidable errors on the part of the caregivers. Because of limited control over seed positioning, prostate contouring uncertainty, and edema,  10-20% variations in the delivered-to-prescribed dose ratios are encountered in normal practice. Thus it is challenging to develop a criterion that detects poor quality implants with high sensitivity but does not wrongly classify an unacceptable number of clinically acceptable implants as MEs. We will review and compare the following ME criteria: (i) the current 10 CFR 35.3045 criterion with the Veteran’s Administration Blue Ribbon Panel recommended implementation; (ii) the ASTRO/US NRC ACMUI source-strength based criterion; and (iii) the dose-based approach currently endorsed by US NRC Staff. These criteria will be assessed using the VA Blue Ribbon Panel’s analysis of RTOG 0232 dose outcomes and the Philadelphia VAMC implant data reported by Hagan et al (In Press, Brachytherapy) Blue Ribbon Panel. These data support the Working Group’s recommendation that the definition of medical event in permanent brachytherapy be based upon the source strength (air-kerma strength) administered.