Estimation of the optimal brachytherapy utilization rate in the treatment of gynecological cancers and comparison with patterns of care

Purpose: We aimed to estimate the optimal proportion of all gynecological cancers that should be treated with brachytherapy (BT)-the optimal brachytherapy utilization rate (BTU)-to compare this with actual gynecological BTU and to assess the effects of nonmedical factors on access to BT. Methods and Materials: The previously constructed inter/multinational guideline-based peer-reviewed models of optimal BTU for cancers of the uterine cervix, uterine corpus, and vagina were combined to estimate optimal BTU for all gynecological cancers. The robustness of the model was tested by univariate and multivariate sensitivity analyses. The resulting model was applied to New South Wales (NSW), the United States, and Western Europe. Actual BTU was determined for NSW by a retrospective patterns-of-care study of BT; for Western Europe from published reports; and for the United States from Surveillance, Epidemiology, and End Results data. Differences between optimal and actual BTU were assessed. The effect of nonmedical factors on access to BT in NSW were analyzed. Results: Gynecological BTU was as follows: NSW 28% optimal (95% confidence interval [CI] 26%-33%) compared with 14% actual; United States 30% optimal (95% CI 26%-34%) and 10% actual; and Western Europe 27% optimal (95% CI 25%-32%) and 16% actual. On multivariate analysis, NSW patients were more likely to undergo gynecological BT if residing in Area Health Service equipped with BT (odds ratio 1.76, P=.008) and if residing in socioeconomically disadvantaged postcodes (odds ratio 1.12, P=.05), but remoteness of residence was not significant. Conclusions: Gynecological BT is underutilized in NSW, Western Europe, and the United States given evidence-based guidelines. Access to BT equipment in NSW was significantly associated with higher utilization rates. Causes of underutilization elsewhere were undetermined. Our model of optimal BTU can be used as a quality assurance tool, providing an evidence-based benchmark against which actual patterns of practice can be measured. It can also be used to assist in determining the adequacy of BT resource allocation.