Trend analysis of radiation therapy incidents over seven years

To examine incident rates in external beam radiation therapy (RT) as significant changes in technology were introduced.

From 2001 to 2007, several technological and practice enhancements were made. All treatment incident reports, including near misses (from 2004), were classified, under a research ethics board approval, according to type (prescription or geometry), cause (location, documentation, non-compliance, laterality, prescribed change, human error, planning/dosimetry, software/hardware malfunction, and accessory), and clinical impact (none, minor, moderate, and severe). Trend analysis was performed retrospectively.

One thousand and sixty three reports were analyzed. The average incident rate per 100 RT course was 1.7+/-0.4; excluding near misses, this rate fell to 1.4+/-0.3. Both rates showed a downward trend. The occurrence of events due to treatment accessories (0.75-0.28), prescribed changes to treatment parameters (0.17-0.03), and location (0.41-0.17) have decreased, while documentation-related incidents have risen (0.03-0.37). The proportion of incidents is highest at the planning and treatment stages.

Our analysis has shown that while technological and process enhancements can reduce certain error pathways, others can be created. Trends in incident rates have been assessed, indicating robustness of our practice in view of these changes.