Journal of Clinical Oncology, Vol 16, 551-556, Copyright © 1998 by American Society of Clinical Oncology
Error rates in clinical radiotherapy
RM Macklis, T Meier and MS Weinhous
Department of Radiation Oncology, The Cleveland Clinic Foundation, OH 44195, USA. macklis@radonc.ccf.org
PURPOSE: Error rates in clinical oncology are undergoing increasing
scrutiny. The purpose of this study was to understand error frequency,
error patterns, underlying causal links, consequences, and possible
prevention strategies in clinical radiotherapy. PATIENTS AND METHODS:
Treatment information, self-reported error documentation, and retrospective
analyses of electronic treatment verification transcripts for 1,925
consecutive patients treated with a total of 93,332 individual radiotherapy
fields were reviewed and analyzed. RESULTS: A total of 59 separate errors
that affected 168 individual treatment fields were detected, which yielded
a crude radiation delivery error rate of 0.18%. All 59 errors were judged
to be level I (negligible chance of adverse medical outcome) with the most
common error category being a minor treatment field block misplacement. A
comprehensive quality assurance program and an electronic record-and-verify
linear accelerator interlock system seem to have prevented the occurrence
of many additional errors. However, nine of the 59 errors were directly
related to the use of this system and generally involved the transposition
of similar numbers within series of treatment coordinate data-sets.
Overall, radiotherapy error rates favorably compare with reported error
rates for pharmaceutical administration in large tertiary care hospitals.
CONCLUSION: When modern automated error- minimization methods are used
along with nonpunitive error reporting systems, clinical radiotherapy seems
to be highly safe. Formal error analysis studies may allow the rational
design of prevention strategies that are attuned to the frequency,
seriousness, and antecedent causes of many classes of potential
radiotherapy errors.
