Physicians' and midlevel providers' awareness of lifetime radiation-attributable cancer risk associated with commonly performed CT studies: relationship to practice behavior

Abstract

Objective: The purpose of this study is to investigate emergency department (ED) providers' knowledge of the lifetime cancer risk attributable to radiation from commonly performed CT scans and its association with the ordering providers' risk-benefit analysis before ordering the examination. This study further explores factors that may influence a provider's selection of a particular diagnostic imaging study in an ED setting.

Materials and methods: Sixty-seven ED providers at the University of Rochester Medical Center completed a multiple-choice questionnaire. The questions were derived to assess an individual provider's awareness of lifetime cancer risk attributable to radiation from a diagnostic CT scan of the abdomen or pelvis and the provider's behavior toward risk-benefit analysis before ordering the examination. The association between the questions and years since completion of clinical training was determined using the Spearman correlation test. Univariate logistic regression analysis was used for the same questions to predict the knowledge of lifetime cancer risk attributable to radiation.

Results: Fewer than 30% of ED providers possessed accurate knowledge of lifetime cancer risk attributable to radiation (p = 0.025). Providers with greater clinical experience, although lacking in the knowledge of lifetime cancer risk attributable to radiation, were more likely to consider patients' radiation dose history and to conduct a risk-benefit analysis and were less likely to order a CT scan unnecessarily. Clinical experience was negatively correlated with perceived unnecessary use of CT scans (p = 0.01).

Conclusion: A large proportion of ED providers are unaware of the lifetime risk of carcinogenesis associated with commonly performed CT scans. Clinical experience, not knowledge of lifetime cancer risk attributable to radiation, is significantly associated with beneficial behavior toward the use of CT.

Figure 1. Frequencies of Estimated Lifetime Increased Risk from One CTAP

QUESTION: IN YOUR JUDGMENT AS A RESULT OF A CT SCAN OF THE ABDOMEN AND PELVIS, BY HOW MUCH IS THE LIFETIME RISK OF DEVELOPING A CANCER INCREASED?”

Figure 2. Frequency distribution of awareness of difference in radiation risk by age

QUESTION: GIVEN THE SAME AMOUNT OF RADIATION DOSE FROM A CT SCAN; DO YOUNGER PATIENTS LESS THAN 30 YRS OF AGE HAVE A HIGHER RISK OF DEVELOPING A CANCER THAN THOSE OVER THE AGE OF 50 YRS?

Figure 3. Frequency Distribution of Perceived Unnecessary Use of CT Scan

QUESTION: HOW OFTEN IN YOUR PRACTICE AFTER OBTAINING THE RESULTS OFTHE CT SCANS YOU FEEL THAT THE CT SCAN WAS PROBABLY UNNECESSARY?