Taxonomy aims to improve muddled radiotherapy error classifications

A practice-based taxonomy for radiotherapy errors developed in Canada has shown the potential to be able to improve communication and aid in quality improvement efforts.

“Our multiphase, iterative approach has yielded a workable and multidimensional set of incident classifiers that can be scaled to accommodate local, regional and discipline-specific requirements,” wrote Catarina Lam, MBA, of University Health Network, Toronto, and colleagues. “Opportunities exist to implement this taxonomy in institutional and national incident databases to facilitate incident learning within and between institutions.”

The authors described the development of this taxonomy in an article published online Oct. 21 in the Journal of Medical Imaging and Radiation Sciences.

Lam and colleagues noted that radiotherapy is complex and error prone, and that high levels of oversight and quality assurance are needed to improve care. However, this type of oversight is more difficult without a common language for incident classification. Previous taxonomies have proven to be either overly complex or too generic to be useful.

In creating and testing their own taxonomy, the authors used a three-phase process. First, they used the World Health Organization Conceptual Framework for the International Classification for Patient Safety, as well as other taxonomy models, to draft an initial version of the taxonomy. Next, they evaluated and revised the taxonomy using incident data from a single practitioner before finally conducting validity testing using simulated incident cases from two other practitioners.

The taxonomy was structured to include seven classes of definitions:

• Incident nature – Describes whether or not incidents reached the patient.
• Impact – Describes the impact of an incident on the patient or organization.
• Incident type – A description of the different categories of incidents.
• Stage of origin – Describes when in the process of radiotherapy the incident occurred.
• Stage of discovery – Describes when in the process of radiotherapy the incident was discovered.
• Contributing factors – A description of all the circumstances or actions that increased the risk of a given incident.
• Preventative strategies – A description of the steps taken to prevent a similar incident.

Each class was divided into progressively detailed subcategories. For instance, an incident involving missing or unavailable documents would fall in the “Documentation” subcategory under the class of “Incident type.”

Early in the validation phase, Lam and colleagues documented a low interobserver agreement of less than 60 percent for most of taxonomy’s classes. However, after revisions were made based on the practitioners’ feedback, a subsequent validity test showed significant improvement, with interobserver agreement ranging between 70 percent and 93 percent for all classes.

The authors said the next step will be the continued evaluation of the taxonomy by an increasing number of practitioners to further refine its design. “Such work needs to be supported by organizations in the radiotherapy community with the resources and vested interest in improving quality and safety.”