Fenton JJ, Lee CI, Xing G, Baldwin L, Elmore JG. Computer-Aided Detection in MammographyDownstream Effect on Diagnostic Testing, Ductal Carcinoma In Situ Treatment, and Costs. JAMA Intern Med. 2014;174(12):2032-2034. doi:10.1001/jamainternmed.2014.5410
Since 2001, Medicare has reimbursed computer-aided detection (CAD) during screening mammography. The CAD software tool is used by radiologists to identify lesions suggestive of malignant disease. Research suggests that CAD use increases the rate of false-positive findings of screening mammography and the detection of ductal carcinoma in situ (DCIS).1 Increased DCIS detection could lead to overdiagnosis of breast cancer, particularly among older women at risk for competing causes of death. We estimated the fraction of diagnostic tests, DCIS treatments, and costs attributable to CAD dissemination within the Medicare population, among whom the risk for overdiagnosis may be elevated.
This study was approved by the institutional review board of the University of California, Davis. Informed consent was waived. Using Surveillance, Epidemiology, and End Results Medicare-linked data from January 1, 2001, through December 31, 2009, we identified screening mammograms performed on female Medicare enrollees aged 67 to 89 years,2 classified mammograms by CAD use, and computed the annual prevalence of CAD use. Using annual prevalences and CAD-associated incident rate ratios from a Medicare cohort study,1 we estimated annual attributable fractions for diagnostic mammography, ultrasonography of the breast, biopsy of the breast, and DCIS diagnoses. We also computed the attributable fraction assuming 100% CAD prevalence because nearly all US mammography units are now digital,3 and digital units typically have integrated CAD.
Extrapolating to the entire US fee-for-service Medicare population, we used incidence rate differences to estimate the number of women who underwent diagnostic testing for breast cancer or who were diagnosed as having DCIS on account of CAD use each year. We used 2013 mean Medicare reimbursement rates and published diagnostic and treatment costs (adjusted to 2013 US dollars) to estimate annual Medicare costs attributable to CAD.4
From January 1, 2001, through December 31, 2009, annual CAD prevalence among Medicare screening mammograms increased from 3.5% to 79.7%. By 2009, 18.2% of diagnostic mammograms, 5.3% of breast ultrasonograms, 7.4% of breast biopsies, and 11.9% of DCIS diagnoses were attributable to CAD (Table 1). From 2001 through 2009, 4612 additional fee-for-service Medicare enrollees were treated for DCIS on account of CAD. If CAD were applied to all Medicare screening mammograms, 14.5% of all DCIS diagnoses would be attributable to CAD, and 1118 additional Medicare enrollees would undergo DCIS treatment each year.
From 2001 through 2009, Medicare total costs for CAD use totaled $278 564 950, including $163 443 470 for supplemental fees, $53 812 033 for downstream diagnostic and interventional procedures, and $61 690 112 for DCIS treatments. If CAD were used on all Medicare screening mammograms, CAD-associated Medicare costs would exceed $67 million annually (Table 2).
Among Medicare enrollees undergoing screening mammography in 2009, approximately 1 in 6 diagnostic mammograms, 1 in 14 breast biopsies, and 1 in 9 DCIS diagnoses were attributable to CAD. From 2001 through 2009, CAD use cost Medicare more than $278 million, most of which accrued in the latter years as CAD prevalence approached 80%. The annual Medicare costs of CAD use would exceed $67 million if CAD were used on all mammograms, representing an approximately 7% increase in the approximate $1 billion annual Medicare costs for breast cancer screening.5
The long-term implications of increased DCIS detection in the Medicare population are uncertain. On one hand, the intent of screening is to detect breast cancers earlier when treatments can be curative and less morbid. However, many DCIS lesions may be overdiagnosed, particularly in an older population.
Our cost analysis takes the perspective of the Medicare program; fiscal effects of CAD across the entire screening population are likely to be much higher.6 CAD-associated incident rate ratios may reflect the clinical effect of CAD use early in its dissemination1; longer-term effects may differ.
Because of broad dissemination in the United States, CAD likely accounts for a substantial fraction of diagnostic breast imaging, breast biopsies, and DCIS diagnoses among the Medicare population, with high resultant costs.
Corresponding Author: Joshua J. Fenton, MD, MPH, Department of Family and Community Medicine, University of California, Davis, 4860 Y St, Ste 2300, Sacramento, CA 95817 (firstname.lastname@example.org).
Published Online: October 27, 2014. doi:10.1001/jamainternmed.2014.5410.
Author Contributions: Dr Fenton had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Fenton, Elmore.
Acquisition, analysis, or interpretation of data: Fenton, Lee, Xing, Baldwin.
Drafting of the manuscript: Fenton, Lee.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Fenton, Xing.
Obtained funding: Fenton.
Administrative, technical, or material support: Lee, Baldwin.
Study supervision: Fenton.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by by the National Center for Advancing Translational Sciences, National Institutes of Health, through grant UL1 TR000002; by the Center for Healthcare Policy and Research, UC Davis; and by grant KO5 CA 104699 from the National Cancer Institute.
Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Previous Presentation: This paper was presented at the First Annual Preventing Overdiagnosis Conference; September 10, 2013; Hanover, New Hampshire.