Evolution of breast cancer screening in the Medicare population: clinical and economic implications

Abstract

Background: Newer approaches to mammography, including digital image acquisition and computer-aided detection (CAD), and adjunct imaging (e.g., magnetic resonance imaging [MRI]) have diffused into clinical practice. The impact of these technologies on screening-related cost and outcomes remains undefined, particularly among older women.

Methods: Using the Surveillance, Epidemiology, and End Results-Medicare linked database, we constructed two cohorts of women without a history of breast cancer and followed each cohort for 2 years. We compared the use and cost of screening mammography including digital mammography and CAD, adjunct procedures including breast ultrasound, MRI, and biopsy between the period of 2001 and 2002 and the period of 2008 and 2009 using χ(2) and t test. We also assessed the change in breast cancer stage and incidence rates using χ(2) and Poisson regression. All statistical tests were two-sided.

Results: There were 137150 women (mean age = 76.0 years) in the early cohort (2001-2002) and 133097 women (mean age = 77.3 years) in the later cohort (2008-2009). The use of digital image acquisition for screening mammography increased from 2.0% in 2001 and 2002 to 29.8% in 2008 and 2009 (P < .001). CAD use increased from 3.2% to 33.1% (P < .001). Average screening-related cost per capita increased from $76 to $112 (P < .001), with annual national fee-for-service Medicare spending increasing from $666 million to $962 million. There was no statistically significant change in detection rates of early-stage tumors (2.45 vs 2.57 per 1000 person-years; P = .41).

Conclusions: Although breast cancer screening-related costs increased substantially from 2001 through 2009 among Medicare beneficiaries, a clinically significant change in stage at diagnosis was not observed.

Figure 1.

Creation of study sample. We included women who were part of the Surveillance, Epidemiology, and End Results–Medicare 5% sample, who did not have a history of breast cancer at the beginning of each study period. This sample includes some women who would later develop breast cancer, as well as women who did not develop breast cancer. We followed the steps in the figure to create the sample.

Figure 2.

Use of breast cancer procedures according to time period. There were 137150 women in the early cohort (2001–2002) and 133097 women in the later cohort (2008–2009). The percentages of women in the early and late cohorts who underwent screening (A) and adjunct testing procedures (B) are shown. Other imaging includes positron emitting tomography imaging; computed tomography of head, brain, thorax, abdomen; magnetic resonance imaging (MRI) of brain, brainstem; radiologic examination of surgical specimen; three-dimensional rendering; bone and joint imaging; and radiopharmaceutical localization of tumor. Error bars represent 95% confidence intervals. CAD = computer-aided detection.

Figure 2.

Use of breast cancer procedures according to time period. There were 137150 women in the early cohort (2001–2002) and 133097 women in the later cohort (2008–2009). The percentages of women in the early and late cohorts who underwent screening (A) and adjunct testing procedures (B) are shown. Other imaging includes positron emitting tomography imaging; computed tomography of head, brain, thorax, abdomen; magnetic resonance imaging (MRI) of brain, brainstem; radiologic examination of surgical specimen; three-dimensional rendering; bone and joint imaging; and radiopharmaceutical localization of tumor. Error bars represent 95% confidence intervals. CAD = computer-aided detection.

Figure 3.

Stage-specific cancer incidence and total Medicare screening-related cost according to time period. There was no statistically significant change in the incidence of early-stage (in situ and stage I) disease (2.45 per 1000 person-years in the early cohort [258118 person-years] to 2.57 per 1000 person-years in the late cohort [251114 person-years]). Similarly, the incidence of late-stage (stage IV) disease did not change statistically significantly over time; it was 0.20 per 1000 person-years in the early cohort and 0.23 per 1000 person-years in the late cohort. During this same time period, there was an absolute increase in Medicare spending for breast screening-related procedures from $666 million in the early period to $962 million in the later period, a 44% increase.