Saving Women's Lives Strategies for Improving Breast Cancer Detection and Diagnosis (2005) / Chapter Skim
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3 Improving Breast Cancer Screening Services
3 Improving Breast Cancer Screening Services
Pages 63-122
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From page 63... ...
This chapter reviews alternative approaches to the organization of breast screening services, ways that mammography could be improved, technologies that might augment or replace mammography in breast cancer screening, and the challenges in supporting and developing a well-trained workforce. SCREENING OUTCOMES VARY BY COUNTRY Nearly a dozen countries have national or regional screening programs in which personal invitations for regular mammograms are sent to all women over age 40 or 50, depending on the country (Table 3-1)
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From page 64... ...
viBased on 2001-2002 data; NHS Breast Screening Programme Annual Review 2003. viiBased on WE trial 1977-1979; attendence after first invitation; Lynge et al.
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From page 65... ...
xiii Initial only. xivThe Mammography Quality Standards Act ensures x-ray technical quality but does not review quality of interpretation.
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From page 66... ...
Screening programs can be compared according to a variety of measures, such as differences in breast cancer survival rates, rates of abnormal mammograms, or rates of false positives. But there are caveats to each of these measures.
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From page 67... ...
. A review of 32 studies showed that the screening programs with high rates of abnormal mammograms also tended to be those with lower positive predictive values for biopsies, suggesting that many of those biopsies could have been safely avoided.36 The data collected in the screening studies reviewed do not permit determination of the underlying causes of the variation in the percentage of mammograms that are judged to be abnormal and the predictive value of biopsies.
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From page 68... ...
That same year, the national breast screening program was established, and it is now one of the most well-established, well-analyzed, and extensive screening programs in the world. Since then, the United Kingdom has had the greatest reduction in breast cancer mortality for Europe.19 There are several important differences in the delivery of breast screening services in the United States and other countries (Table 3-2)
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From page 69... ...
· Quality assurance standards concerning mammographic interpreta tion for the National Health Service Breast Screening Program are set nationally and are regularly monitored through a quality assur ance network. Although the threat of malpractice is frequently cited as an important reason for the difference in screening practices between the two countries, this is part of the larger context of the health care and can not be regulated through breast cancer screening programs.
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From page 70... ...
70 for included sets sets U.S. estimates estimates of biopsy set; data of data of of significant studies; studies of significantly test high-volume specificity two two not not median median subsequent more more types for with groups.
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From page 71... ...
71 two (18 based in data therefore, studies. estimates UK U.K.
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From page 72... ...
Mammography services in both Sweden and several Canadian provinces also have high performance standards, but there are fewer published data and direct comparisons with services in the United States, so they are not reviewed here. The British Health Service monitors and tracks the outcomes of their breast cancer screening programs more thoroughly than do other countries.74 QUALITY ASSURANCE IMPROVES OUTCOMES The National Health Service Breast Screening Programme (NHSBSP)
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From page 73... ...
recall, biopsy, and cancer detections rates have been established and an organized program operates at the local and national levels to monitor and achieve these targets. All screening programs in the United Kingdom receive data that enable a comparison of their recall and cancer detection rates with other programs.
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From page 74... ...
to study ways that the MQSA could be improved both to improve the quality of mammographic interpretation and to ensure an adequate workforce. Adopting Best Practices from Other Countries Can Save Lives Mammographic screening services in the United States are typically separated from treatment, counseling, and other support services.
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From page 75... ...
Callback rates in mammography screening can be reduced when mammograms are read by breast imaging specialists at a central location, as opposed to having them dispersed among the sites where the mammography is done. By centralizing the reading, the mammography service reduced the overall callback rate by 2 percent, from 11 to 9 percent, which was statistically significant.76 On the other hand, the quality of a breast cancer screening program cannot be measured solely by the recall rate or the cancer detection rate, although these are important considerations.
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From page 76... ...
Low socioeconomic status is characterized by low income, higher rates of poverty, lower levels of education, lack of private health insurance, lack of transportation, and lack of access to health care. Together, these factors are associated with lower rates of cancer screening, higher probability for later stage diagnosis, lack of breast health awareness, and mistrust and misunderstanding of the health care system.28,60,61,71,91,95 Higher poverty rates among African Americans are reflected in disproportionate numbers of women lacking adequate insurance, or any insurance at all.47,90 Insurance coverage is a significant predictor of whether or not a woman will receive a mammogram.57 Uninsured women and women with Medicaid are more likely to receive a breast cancer diagnosis at a late stage of disease, and are 30 to 50 percent more likely to die of their disease than women with private insurance.57 Yet when white, African-American, and Hispanic women were provided equal access to high-quality mammographic screening, all groups had similar rates of breast cancer survival regardless of age, stage of diagnosis, and socioeconomic status.123 These circumstances are, however, far from typical (Figure 3-3)
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From page 77... ...
IMPROVING BREAST CANCER SCREENING SERVICES 77 A 160 140 120 100 100,000 per 80 Rate 60 40 20 0 1973 1978 1983 1988 1993 1998 Year of diagnosis All races White Black B 45 40 35 30 25 100,000 per 20 Rate 15 10 5 0 1969 1974 1979 1984 1989 1994 1999 Year of death All races White Black FIGURE 3-2 Breast cancer incidence (A) and mortality (B)
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From page 78... ...
National Breast and Cervical Cancer Detection Program was launched in 1990 to provide screening services for uninsured women who were not eligible for Medicaid. Since then it has provided nearly 4 million screenings to 1.6 million women.
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From page 79... ...
Community-based programs, such as the North Carolina Breast Cancer Screening Program, also disseminate information about prevention and guide women to mammographic services.32 Equal access is a prerequisite for reducing the unequal burden of breast cancer, but other factors that contribute to equal use of health care services are also critical and must be taken into account. IMPROVING MAMMOGRAPHY Quality Assurance by Law Mammography is possibly the most heavily legislated medical procedure in history.
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From page 80... ...
The legislation also increased payments for mammography and provided an additional $10 million in funding for the National Breast and Cervical Cancer Early Detection Program, bringing the total to $220 million. The program is intended to provide 32,000 diag nostic and screening services to additional women who are hard to reach and have never been screened for these cancers.
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From page 81... ...
· Authorized HHS grants for research on the effectiveness of breast cancer screening programs. 1990 Omnibus Budget Reconciliation Act Reauthorized Medicare payment and certification standards for screening mam mography for women.
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From page 82... ...
The MQSA includes requirements that breast imaging facilities performing mammography must be certified by the Secretary of Health and Human Services and be accredited by an approved body (see Box 3-4)
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From page 83... ...
The MQSA regulations set standards primarily for the technical quality of mammography, whereas quality standards for the interpretation of mammography are almost nonexistent. The only regulation relating to quality of interpretation requires that physicians who interpret mammograms must interpret a minimum of 960 mammograms every two years, an average of 480 per year (see following discussion under Variation in Mammographic Interpretation)
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From page 84... ...
It is intended to guide radiologists and referring physi cians in a decision-making process that facilitates the management of patients based on breast imaging. BI-RADS® is a useful and widely used tool for standardizing the interpretation of mammograms and for quantitative analysis.
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From page 85... ...
Many factors influence the accuracy of individual radiologists in recognizing clinically important abnormalities during screening mammography, but many other factors influence the consistency of mammographic interpretation (reviewed by Beam, Elmore, Sickles, and colleagues 7,15,35,41,105 )
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From page 86... ...
Breast cancer history Family history of breast cancer63 Previous biopsy Practice Variation Individual radiologists Subspecialty training in breast imaging Volume of mammograms read (but see text) Years since training Organization of · High volume centers tend to have higher accuracy, mammography services above and beyond the increase attributable to reading volume of individual radiologists · Number of diagnostic exams performed · Number of image-guided breast interventional procedures (biopsies?
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From page 87... ...
Therefore -- if judged by rates of false positives -- the apparent performance of a mammography service or individual radiologist would be influenced by the proportion of how many women are receiving their first mammogram. Performance and Volume A relationship between the volume of procedures performed and the outcome of those procedures has been established for many complex medical procedures, particularly in surgery and oncology.55 Many studies have suggested that the volume of mammograms read by a radiologist is correlated with accuracy, and mammography volume standards are mandated by federal law.
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From page 88... ...
88 percent read for the 37 and 61 the sensitivity for with equal (2,000- significant volume low- these rates not 11 perform No cancer, re, Inconsistent was higher (77%)
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From page 89... ...
Leonard Berlin testified on behalf of the ACR in Congress that malpractice suits in the United States are decided in favor of plaintiffs so often that many radiologists do not attempt to contest even seemingly frivolous cases.14 Rates of false positives in the Unites States nearly doubled from 1985 to 1993, from roughly 5 to 10 percent.35 This increase parallels the steadily increasing rates of malpractice suits related to failures to detect breast cancer through mammography, which is often proposed as a driving force in rates of false positives. Radiologists in the United States may be practicing more defensive medicine because they fear malpractice suits, which their counterparts in the United Kingdom face to a much lesser degree.34 Although British radiologists also report that they worry about malpractice, the scope of the problem is considerably less than it is in the United States.
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From page 90... ...
They include increasing the required volume of mammograms, restricting the number of radiologists permitted to interpret mammograms, greater standardization of assessment categories, public reporting of performance, and better training for radiologists in mammographic interpretation. Increase Volume Requirements The MQSA standards for the minimum number of mammograms to be interpreted by certified radiologists are lower in the United States than for other countries with breast screening programs (Table 3-5)
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From page 91... ...
Agreement among radiologists is also lower for mammograms of women with dense breasts.69 Public Reporting of Performance Publicly reporting mammogram interpretation performance results of radiologists has been resisted by radiologists. Quality conclusions based on performance might be misleading in view of differing risks, ages, or other characteristics of caseload among radiologists and facilities that could legitimately lead to differing results, as noted earlier.
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From page 92... ...
OTHER TECHNOLOGY OPTIONS As noted earlier, no breast cancer screening tool has better sensitivity and specificity than screen-film mammography, although it could be better. However, even with similar sensitivity and specificity, there may be ways to improve storage, transmission, cost, ease of use, and other characteristics of mammography that would add value.
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From page 93... ...
Overall, there were no major differences in cancer detection rates between the two techniques, although if the digital technique had been used alone, recall rates would have been lower.70 Similar results were reported in 2003 from a Norwegian study of 3,683 women.106 Each woman in the study had both digital and screen film mammography exams and they were independently interpreted. The cancer detection rates for the two imaging modalities were not significantly different, although the recall rate was slightly higher for digital mammography and the positive predictive value based on needle biopsy was slightly higher for screen film mammography.
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From page 94... ...
Using ImageChecker®, Zheng scanned the images three times over a period of 3 weeks, checking for sensitivity, false-positive rates, and reproducibility of the results. The researchers found identical results in 213 of 400 images, for a reproducibility rate of 53 percent, an improvement from 38 percent found in a 2000 study based on an earlier version of the CAD system.125 The greatest clinical value in CAD probably does not lie in its ability to raise the performance level of all breast imagers, but rather in its potential
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From page 95... ...
An often overlooked challenge in establishing the value of CAD systems is that they are not all the same. There has been a series of peerreviewed papers documenting the efficacy of the CAD systems produced by R2 Technology, but, to date, there are no peer-reviewed reports on the efficacy of any other commercially available CAD systems for breast imaging.
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From page 96... ...
Gradishar, M.D. Northwestern University Researchers have been exploring the use of MRI in breast cancer detection for more than 15 years.104 In 1991, the FDA cleared MRI for use as a diagnostic tool to evaluate breast tissue abnormalities found in other exams -- but not as a screening tool.
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From page 97... ...
A prospective study of 51 patients with biopsy-proven DCIS who underwent contrast-enhanced MRI before surgical treatment indicated that contrast-enhanced MRI had significantly higher sensitivities and negative predictive values than mammography in the detection of residual disease, occult invasive cancer, and multicentric DCIS.53 Although contrast-enhanced MRI was statistically significantly more accurate than mammography for detecting multicentric DCIS, it was significantly less specific than mammography for detecting associated invasive disease.53 It is important to keep in mind that results for MRI based on high-risk
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From page 98... ...
In addition, the lower specificity of MRI compared to mammography would translate into a substantially higher rate of false positives. According to Daniel Sullivan, Associate Director for the Cancer Imaging Program at the NCI, determining the value of MRI screening for the general population would require a study of more than 40,000 patients, a minimum of 3 years, and tens of millions of dollars.84 Unfortunately, the lack of evidence in support of MRI for breast cancer screening and the lack of FDA approval do not necessarily protect the public from misleading marketing (see Box 1-3 in Chapter 1)
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From page 99... ...
.66 However, because breast screenings were not conducted independently in any of these studies, their results were potentially biased (for example, by researchers' knowledge of a participant's mammography findings prior to conducting ultrasound) .66 Better information on the potential role of ultrasound in breast cancer screening should be forthcoming from a multicenter clinical trial that is currently being conducted by ACRIN with support from the Avon Foundation (see Chapter 6)
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From page 100... ...
The need for and difficulty in developing a large and well-trained workforce will likely help to push for research and adoption of technology that improves our ability to target mammographic screening to those who will benefit most. This section describes key factors influencing supply and demand for breast imaging and recommended measures to ensure the accessibility and advancement of breast cancer screening.
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From page 101... ...
Although no published studies document this trend, there is widespread consensus among breast imagers that workforce issues limit access to mammography and this problem is becoming more acute. A 2002 report by the GAO found that women in some locations have problems obtaining timely mammography services and raised the prospect of future staff shortfalls, but concluded that the nation's capacity was "generally adequate to meet the growing demand for these services."119 Impressions of current capacity within the field of breast imaging are far less sanguine, and that community has criticized the GAO report on several counts.85 For example, they note that it does not distinguish among those radiologists who read some mammograms and those who are breast imaging subspecialists,c and therefore may have overestimated capacity for mammogram interpretation.
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From page 102... ...
and the cost of compliance with MQSA regulations.56 Medicare now pays slightly more than $82 per mammogram; the ACR estimates that a screening mammogram costs about $87 to perform in a freestanding 10,000 FDA 9,000 the by 8,000 Inspected 7,000 Facilities of 6,000 Number 5,000 2000 2001 2002 2003 est.* Inspection Year FIGURE 3-6 Fewer mammography facilities each year.
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From page 103... ...
, they spend more of their time doing breast imaging than other radiologists and tend to be more proficient. Thus increasing their ranks may not only help meet the growing demand for screening mammograms, but also improve the quality of breast image interpretation.
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From page 104... ...
9The same proportion of respondents said they did not want to spend more than 25 percent of their work time interpreting mammograms, due to reasons such as lack of interest, fear of lawsuits, high stress, low pay, and the fact that breast imaging is perceived as a female-dominated field. Even without a general shortage of radiologists for procedures other than mammography, there is great concern over the shortage of breast imagers.
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From page 105... ...
These could include the reorgani zation of breast cancer screening services to better serve young women at higher than-average risk for breast cancer, improving the quality of mammographic inter pretation, and developing more effective technologies to detect and diagnose breast cancer.
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From page 106... ...
Radiologists, and particularly breast imaging subspecialists, are needed to refine,
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From page 107... ...
. This is a loss not only because breast imagers are less available to contribute their perspectives to research on improving breast cancer detection, but they are also deprived of an opportunity to learn about new directions in research.
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From page 108... ...
The latter situation may occur if recruitment into the field of breast imaging fails to keep pace with the demand for screening, but it may also result from technical and regulatory demands that increase workload.
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From page 109... ...
The speed of adoption for new technologies and evidence-based practice guidelines for breast cancer detection is likely to vary according to region (urban versus rural) and clinical setting (community clinic versus academic health center)
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From page 110... ...
Visa restrictions, in addition to the burden of state and hospital licensure and ACR certification requirements, inhibit the immigration of highly qualified foreign radiologists. Given these circumstances, the committee focused on optimizing the productivity of the limited and increasingly precious supply of radiologists who interpret mammograms.
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From page 111... ...
While RAs would enable breast imagers to focus on image interpretation and biopsies, physician extenders who interpret screening mammograms under the supervision of breast imaging specialists can further extend capacity. Evidence suggests that RTs could be specially trained to prescreen mammograms for the presence or absence of abnormalities25,111 or to double-read mammograms along with a radiologist.122 A series of studies supports the prospect for training and evaluation of physician extenders in mammographic interpretation.
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From page 112... ...
Having a physician extender support the work of breast imagers would add the cost of an extra salary, but this could result in overall reduced costs if they could take on other tasks commonly done by radiologists. The most important requirement that would have to be met if nonphysicians were to interpret mammograms would be that the quality of the mammography service was shown to improve, or at least, did not decline.
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From page 113... ...
. · Must complete 40 hours of training specific to mammography · Must perform 200 mammograms every 2 years Medical Physicist -- Surveys mammography equipment and oversees quality assurance practices · Must be state licensed to perform physics survey · Must have a Master's degree or higher in physical science · Must complete 20 hours of specialized training in conducting surveys of mammography facilities · Must conduct surveys of at least 1 mammography facility and a total of 10 mammography units
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From page 114... ...
Organizing breast screening services to increase the utilization of services as well as their quality and efficiency should thus be priority for health care payers and providers. Approaches to improving mammography that need to be examined include organizational changes such as those implemented in some European countries including limiting interpretation to more expert and experienced breast imagers, and regionalization and reading at a central location.
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From page 115... ...
Mettlin Cancer Screening and Early Detection, 2003 State and federal legislators have taken an active role in exploring ways to improve breast cancer detection. The federal Mammography Quality Standards Act represents an unusual governmental intervention aimed at, and successful in, improving the technical quality of mammography.
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From page 116... ...
2001. Pain during mammography: implications for breast screening programmes.
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From page 117... ...
2003. Individual and combined effects of age, breast density, and hormone replacement therapy use on the accuracy of screening mammography.
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From page 118... ...
2003. Cancer Screening and Early Detection.
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From page 119... ...
2000. Standard ized abnormal interpretation and cancer detection ratios to assess reading volume and reader performance in a breast screening program.
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From page 120... ...
Cancer Screening Programmes.
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2004. Cancer screening and the periodic health examination.
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From page 122... ...
2002. Concordance of breast imaging reporting and data system assessments and management recommendations in screening mammography.
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