Costs for Breast Cancer Screening After Digital Mammography
Background Compared with film, digital mammography has superior sensitivity but lower specificity for women aged 40 to 49 years and women with dense breasts. Digital has replaced film in virtually all US facilities, but overall population health and cost from use of this technology are unclear.
Methods Using five independent models, we compared digital screening strategies starting at age 40 or 50 years applied annually, biennially, or based on density with biennial film screening from ages 50 to 74 years and with no screening. Common data elements included cancer incidence and test performance, both modified by breast density. Lifetime outcomes included mortality, quality-adjusted life-years, and screening and treatment costs.
Results For every 1000 women screened biennially from age 50 to 74 years, switching to digital from film yielded a median within-model improvement of 2 life-years, 0.27 additional deaths averted, 220 additional false-positive results, and $0.35 million more in costs. For an individual woman, this translates to a health gain of 0.73 days. Extending biennial digital screening to women ages 40 to 49 years was cost-effective, although results were sensitive to quality-of-life decrements related to screening and false positives. Targeting annual screening by density yielded similar outcomes to targeting by age. Annual screening approaches could increase costs to $5.26 million per 1000 women, in part because of higher numbers of screens and false positives, and were not efficient or cost-effective.
Conclusions The transition to digital breast cancer screening in the United States increased total costs for small added health benefits. The value of digital mammography screening among women aged 40 to 49 years depends on women's preferences regarding false positives.
Over the past decade, digital mammography has rapidly replaced plain film mammography for breast cancer screening in the United States, accounting for 90% of the current market. This conversion was fueled in part by the 2005 Digital Mammographic Imaging Screening Trial (DMIST) report of superior digital mammography sensitivity compared with film for women aged younger than 50 years and for women with dense breasts. Multiple studies and recent reports from community practice show similar results as DMIST, although specificity has been modestly lower for digital mammography than film.
The overall effect of this performance trade-off on population health and economic burden is unclear for several reasons. Dense breast tissue can both mask tumors and increase the risk of breast cancer. Therefore, higher tumor detection among women with dense breasts by digital mammography could improve screening benefits. However, because breast cancer prevalence is low at any single examination, even small decrements in specificity may be associated with large increases in the number of false positives and any associated harms and costs. In the Medicare population, digital mammography has been associated with a higher rate of early-stage cancers but no change in rates of advanced disease and with higher screening and diagnostic costs compared with film. An effect on mortality has not been shown. A prior cost-effectiveness analysis of substituting digital for film mammography based on the DMIST trial assumed equivalent specificity and found that, compared with using digital mammography for all women, greater health gains could be achieved at a lower cost by reserving digital for the subgroups for whom higher sensitivity had been found, with film used in other groups. However, a strategy involving a mix of film and digital mammography is no longer practical in the United States given the transition to virtually fully digital facilities.
To understand the trade-offs involved in this rapid US adoption of new screening technology, we used five established independent models developed within the Cancer Intervention and Surveillance Modeling Network (http://www.cisnet.cancer.gov) in partnership with the Breast Cancer Surveillance Consortium (BCSC; http://www.breastscreening.cancer.gov). We extended our prior collaborative modeling research to consider the impact of breast density on both incidence and test performance in evaluating outcomes from digital vs film screening. The results are intended to contribute to policy discussions about resource allocation and how to best integrate new technology into health care.
Abstract and Introduction
Abstract
Background Compared with film, digital mammography has superior sensitivity but lower specificity for women aged 40 to 49 years and women with dense breasts. Digital has replaced film in virtually all US facilities, but overall population health and cost from use of this technology are unclear.
Methods Using five independent models, we compared digital screening strategies starting at age 40 or 50 years applied annually, biennially, or based on density with biennial film screening from ages 50 to 74 years and with no screening. Common data elements included cancer incidence and test performance, both modified by breast density. Lifetime outcomes included mortality, quality-adjusted life-years, and screening and treatment costs.
Results For every 1000 women screened biennially from age 50 to 74 years, switching to digital from film yielded a median within-model improvement of 2 life-years, 0.27 additional deaths averted, 220 additional false-positive results, and $0.35 million more in costs. For an individual woman, this translates to a health gain of 0.73 days. Extending biennial digital screening to women ages 40 to 49 years was cost-effective, although results were sensitive to quality-of-life decrements related to screening and false positives. Targeting annual screening by density yielded similar outcomes to targeting by age. Annual screening approaches could increase costs to $5.26 million per 1000 women, in part because of higher numbers of screens and false positives, and were not efficient or cost-effective.
Conclusions The transition to digital breast cancer screening in the United States increased total costs for small added health benefits. The value of digital mammography screening among women aged 40 to 49 years depends on women's preferences regarding false positives.
Introduction
Over the past decade, digital mammography has rapidly replaced plain film mammography for breast cancer screening in the United States, accounting for 90% of the current market. This conversion was fueled in part by the 2005 Digital Mammographic Imaging Screening Trial (DMIST) report of superior digital mammography sensitivity compared with film for women aged younger than 50 years and for women with dense breasts. Multiple studies and recent reports from community practice show similar results as DMIST, although specificity has been modestly lower for digital mammography than film.
The overall effect of this performance trade-off on population health and economic burden is unclear for several reasons. Dense breast tissue can both mask tumors and increase the risk of breast cancer. Therefore, higher tumor detection among women with dense breasts by digital mammography could improve screening benefits. However, because breast cancer prevalence is low at any single examination, even small decrements in specificity may be associated with large increases in the number of false positives and any associated harms and costs. In the Medicare population, digital mammography has been associated with a higher rate of early-stage cancers but no change in rates of advanced disease and with higher screening and diagnostic costs compared with film. An effect on mortality has not been shown. A prior cost-effectiveness analysis of substituting digital for film mammography based on the DMIST trial assumed equivalent specificity and found that, compared with using digital mammography for all women, greater health gains could be achieved at a lower cost by reserving digital for the subgroups for whom higher sensitivity had been found, with film used in other groups. However, a strategy involving a mix of film and digital mammography is no longer practical in the United States given the transition to virtually fully digital facilities.
To understand the trade-offs involved in this rapid US adoption of new screening technology, we used five established independent models developed within the Cancer Intervention and Surveillance Modeling Network (http://www.cisnet.cancer.gov) in partnership with the Breast Cancer Surveillance Consortium (BCSC; http://www.breastscreening.cancer.gov). We extended our prior collaborative modeling research to consider the impact of breast density on both incidence and test performance in evaluating outcomes from digital vs film screening. The results are intended to contribute to policy discussions about resource allocation and how to best integrate new technology into health care.