Is the supply of mammography machines outstripping need and demand? An economic analysis

A History of Health Economics and Healthcare Delivery Research at the National Cancer Institute

With increased attention to the financing and structure of healthcare, dramatic increases in the cost of diagnosing and treating cancer, and corresponding disparities in access, the study of healthcare economics and delivery has become increasingly important. The Healthcare Delivery Research Program (HDRP) in the Division of Cancer Control and Population Sciences at the National Cancer Institute (NCI) was formed in 2015 to provide a hub for cancer-related healthcare delivery and economics research. However, the roots of this program trace back much farther, at least to the formation of the NCI Division of Cancer Prevention and Control in 1983. The creation of a division focused on understanding and explaining trends in cancer morbidity and mortality was instrumental in setting the direction of cancer-related healthcare delivery and health economics research over the subsequent decades. In this commentary, we provide a brief history of health economics and healthcare delivery research at NCI, describing the organizational structure and highlighting key initiatives developed by the division, and also briefly discuss future directions. HDRP and its predecessors have supported the growth and evolution of these fields through the funding of grants and contracts; the development of data, tools, and other research resources; and thought leadership including stimulation of research on previously understudied topics. As the availability of new data, methods, and computing capacity to evaluate cancer-related healthcare delivery and economics expand, HDRP aims to continue to support this growth and evolution.

Geographic disparities in mammography capacity in the South: a longitudinal assessment of supply and demand

OBJECTIVE

Studies have shown that there is sufficient availability of mammography; however, little is known about geographic variation in capacity. The purpose of this study was to determine the locations and extent of over/undersupply of mammography in 14 southern states from 2002 to 2008.

DATA SOURCES

Mammography facility data were collected from the U.S. Food and Drug Administration (FDA). Population estimates, used to estimate the potential demand for mammography, were obtained from GeoLytics Inc.

STUDY DESIGN

Using the two-step floating catchment area method, we calculated spatial accessibility at the block group level and categorized the resulting index to represent the extent of under/oversupply relative to the potential demand.

PRINCIPAL FINDINGS

Results show decreasing availability of mammography over time. The extent of over/undersupply varied significantly across the South. Reductions in capacity occurred primarily in areas with an oversupply of machines, resulting in a 68 percent decrease in the percent of women living in excess capacity areas from 2002 to 2008. The percent of women living in poor capacity areas rose by 10 percent from 2002 to 2008.

CONCLUSIONS

Our study found decreasing mammography availability and capacity over time, with substantial variation across states. This information can assist providers and policy makers in their business planning and resource allocation decisions.

Geographic access and the use of screening mammography

BACKGROUND

Screening mammography rates vary geographically and have recently declined. Inadequate mammography resources in some areas may impair access to this technology. We assessed the relationship between availability of mammography machines and the use of screening.

METHODS

The location and number of all mammography machines in the United States were identified from US Food and Drug Administration records of certified facilities. Inadequate capacity was defined as <1.2 mammography machines per 10,000 women age 40 or older, the threshold required to meet the Healthy People 2010 target screening rate. The impact of capacity on utilization was evaluated in 2 cohorts: female respondents age 40 or older to the 2006 Behavioral Risk Factor Surveillance System survey (BRFSS) and a 5% nationwide sample of female Medicare beneficiaries age 65 or older in 2004-2005.

RESULTS

About 9% of women in the BRFSS cohort and 13% of women in the Medicare cohort lived in counties with <1.2 mammography machines per 10,000 women age 40 or older. In both cohorts, residence in a county with inadequate mammography capacity was associated with lower odds of a recent mammogram (adjusted odds ratio in BRFSS: 0.89, 95% CI: 0.80-0.98, P < 0.05; adjusted odds ratio in Medicare: 0.86, 95% CI: 0.85-0.87, P < 0.05), controlling for demographic and health care characteristics.

CONCLUSION

In counties with few or no mammography machines, limited availability of imaging resources may be a barrier to screening. Efforts to increase the number of machines in low-capacity areas may improve mammography rates and reduce geographic disparities in breast cancer screening.

The changing incidence of in situ and invasive ductal and lobular breast carcinomas: United States, 1999-2004

BACKGROUND

National incidence rates for lobular and ductal breast cancers have not been available previously. Evidence suggests that the increased risk of breast cancer associated with combined hormone replacement therapy use is higher for invasive lobular cancers (ILC) than for invasive ductal cancers (IDC). This study provides U.S. incidence rates for these histologic types for both in situ and invasive cancers and assesses changes in the incidence of these cancers over time.

METHODS

Data for this study included incident ductal and lobular breast cancer cases diagnosed from 1999 through 2004 in central cancer registries in 44 states and the District of Columbia from the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results program. We estimated incidence per 100,000 women by 10-year age groups, race, and ethnicity. We also assessed the percent change in invasive and in situ cancer incidence over time.

RESULTS

We observed distinct differences in the change of incidence over time between in situ and invasive lobular and ductal breast cancers. The age-adjusted rates of ILC and IDC declined an average of 4.6% and 3.3% per year, respectively. Overall, ILC decreased 20.5% from 1999 to 2004. The patterns of ductal and lobular in situ cancer incidence were not consistent over time, and the total change was negligible.

CONCLUSION

The declines in ILC observed in our study are consistent with a decrease in cancer incidence related to a reduced use of combined hormone replacement therapy. However, other factors could also be responsible for these changes.

Determinants of the number of mammography units in 31 countries with significant mammography screening

In the 2000s, most of the female population of industrialised countries had access to mammography breast cancer screening, but with variable modalities among the countries. We assessed the number of mammography units (MUs) in 31 European, North American and Asian countries where significant mammography activity has existed for over 10 years, collecting data on the number of such units and of radiologists by contacting institutions in each country likely to provide the relevant information. Around 2004, there were 32,324 MU in 31 countries, the number per million women ranging from less than 25 in Turkey, Denmark, the Netherlands, the United Kingdom, Norway, Poland and Hungary to more than 80 in Cyprus, Italy, France, the United States and Austria. In a multivariate analysis, the number of MUs was positively associated with the number of radiologists (P=0.0081), the number of women (P=0.0023) and somewhat with the country surface area (P=0.077). There is considerable variation in the density of MU across countries and the number of MUs in service are often well above what would be necessary according to local screening recommendations. High number of MUs in some countries may have undesirable consequences, such as unnecessarily high screening frequency and decreased age at which screening is started.

Professional and economic factors affecting access to mammography: A crisis today, or tomorrow?

BACKGROUND

Objective data and anecdotal reports have suggested that access to mammography may be declining because of facility closures and difficulty in recruiting and retaining radiologists and radiologic technologists. To gain insight into the practice patterns, use of emerging technologies, and concerns of breast imagers in current practice, the Society of Breast Imaging (SBI) conducted a national survey of breast imaging practices in the U.S.

METHODS

Between October 2003 and April 2004, the SBI conducted a survey of the SBI membership database, and received completed surveys from 575 breast imaging practices in the U.S. Responses to the survey regarding practice characteristics, the utilization of standard and emerging technologies, staffing, malpractice, finance, and morale were analyzed.

RESULTS

Job vacancies for radiologists who read mammograms were reported in 163 practices (29%), 59 of which (10%) had 2 or more openings. A higher proportion of practices with job openings had long appointment waiting times for asymptomatic women when compared with fully staffed practices. Unfilled fellowship positions also were common, with 41 of 65 practices that offer fellowships reporting 47 openings. Among 554 responding practices, 55% reported that someone in their practice was sued because of a mammography related case within the past 5 years, and 50% of practices reported that the threat of lawsuits made radiologist staffing "moderately" or "a lot" more difficult. Of 521 responding practices, 35% reported financial losses in 2002. One in 5 respondents reported that they would prefer to spend less time in mammography, and fewer than 1 in 3 would recommend a breast imaging fellowship to a relative or friend. Emerging technologies, such as breast magnetic resonance imaging and screening ultrasound, currently are being performed in many practices.

CONCLUSIONS

The survey results provide support for anecdotal reports that breast imaging practices face significant challenges and stresses, including shortages of key personnel, a lack of trainees, malpractice concerns, financial constraints, increased workload due to emerging technologies, low appeal of breast imaging as a career specialty, and the steady rise in the population of women of screening age.

Predicting patterns of mammography use: a geographic perspective on national needs for intervention research

OBJECTIVE

To introduce a methodology for planning preventive health service research that takes into account geographic context.

DATA SOURCES

National Health Interview Survey (NHIS) self-reports of mammography within the past two years, 1987, and 1993-94. Area Resource File (ARF), 1990. Database of mammography intervention research studies conducted from 1984 to 1994.

DESIGN

Bayesian hierarchical modeling describes mammography as a function of county-level socioeconomic data and explicitly estimates the geographic variation unexplained by the county-level data. This model produces county use estimates (both NHIS-sampled and unsampled), which are aggregated for entire states. The locations of intervention research studies are examined in light of the statewide mammography utilization estimates.

DATA EXTRACTION

Individual level NHIS data were merged with county-level data from the ARF.

PRINCIPAL FINDINGS

State maps reveal the estimated distribution of mammography utilization and intervention research. Eighteen states with low mammography use reported no intervention research activity. County-level occupation and education were important predictors for younger women in 1993-94. In 1987, they were not predictive for any demographic group.

CONCLUSIONS

Opportunities exist to improve the planning of future intervention research by considering geographic context. Modeling results suggest that the choice of predictors be tailored to both the population and the time period under study when planning interventions.

The impact of alternative practices on the cost and quality of mammographic screening in the United States

The decentralized structure of health care in the Unites States hinders population-based analysis of breast cancer screening. Our objectives are to model mammography in the United States as a whole, to identify the variables that most profoundly affect cost and efficacy, and to develop a strategy to improve mammography screening from a population perspective. A spreadsheet model was used to represent the variables of mammography screening in the United States. The population-based national screening program in Sweden provides a framework for comparison. The outcome measures are the aggregate cost and the number of cancers detected by mammography. We used deterministic sensitivity analysis to calculate the impact of variation in practice. Aggregate costs of screening in the United States are in the range of $3-$5 billion dollars. The percentage of women screened, cost per mammogram, cancer to biopsy ratio, recall rate, and cost of recall have the most profound effect on the quality and cost of a national screening program. Variance of these high-impact variables, based on the U.S. population, modifies the aggregate cost of screening by over $2 billion. As mammography screening in the United States increases to include all women over age 40, high-impact variables should be optimized to decrease costs and improve breast cancer detection. Our model establishes which parameters are most important.

Increases in ductal carcinoma in situ (DCIS) of the breast in relation to mammography: a dilemma

The increased use of screening mammography has resulted in a marked increase in detected cases of ductal carcinoma in situ (DCIS) of the breast since the early 1980s. In 1993, there were an estimated 23,275 newly diagnosed cases of DCIS in the United States, of which 4,676 were in women aged 40-49. DCIS accounted for 14.7% of all newly diagnosed breast cancers in women aged 40-49 in 1993, and perhaps 40% of all mammographically detected breast cancers in this age group are DCIS. Among women aged 40-49, an estimated 1,890 mastectomies and 2,707 lumpectomies (with or without radiation) were performed for DCIS in 1993. There is an urgent need to better understand the relationship of mammographically detected DCIS to invasive and potentially life-threatening breast cancer. Better information about the appropriate treatment of DCIS is also needed to reduce the confusion and uncertainty many women and their physicians currently experience in the face of a DCIS diagnosis. For the present, women considering screening mammography should be told the likelihood of being diagnosed with DCIS and that only some DCIS cases may be clinically significant but almost all will be treated surgically.

The impact of mammography quality improvement legislation in Michigan: implications for the National Mammography Quality Standards Act

OBJECTIVES

This study examined the impact of state legislation on mammography quality and access in Michigan.

METHODS

The impact of state legislation was analyzed with respect to utilization, numbers of machines and facilities, and image quality.

RESULTS

The legislation had a positive effect on image quality improvement, had no impact on utilization by women aged 50 years and above, and resulted in few facility closures.

CONCLUSIONS

Michigan's legislative intervention appears to have had a positive effect on efforts to improve mammography quality assurance with implications for other federal and state efforts to achieve quality assurance in health care delivery.

A method for partitioning cancer mortality trends by factors associated with diagnosis: an application to female breast cancer

U.S. cancer mortality data derived from information recorded on death certificates are frequently relied upon as an indicator of progress against cancer. A limitation of this measure is the lack of information pertaining to the onset of disease, such as year-of-diagnosis, age-at-diagnosis, stage of disease at diagnosis and histology of lesions. However, population-based cancer registries collect these types of data and allow the calculation of an incidence-file based mortality rate. This incidence-based mortality rate allows a partitioning of mortality by variables associated with the cancer onset. Breast cancer incidence-based mortality measures are created and compared to mortality rates based on death certificates over a comparable time period. Novel mortality measures, such as mortality rates by stage-at-diagnosis, age-at-diagnosis and year-of-diagnosis, are used to illustrate the value of this approach.

Changes in the use of screening mammography: evidence from the 1987 and 1990 National Health Interview Surveys

OBJECTIVES

Mammography rates reported by women in the National Health Interview Surveys of 1990 and 1987 are examined. Why this screening modality is not more frequently used is explored.

METHODS

Data from the 1987 and 1990 National Health Interview Surveys, conducted by the National Center for Health Statistics, are cross-tabulated and compared.

RESULTS

In 1987, approximately 17% of women over 40 years of age reported having had a screening mammogram in the previous year. In 1990, the rate doubled. Race declined in importance; income and education remained strong, positive predictors of screening.

CONCLUSIONS

Despite this dramatic increase, two thirds of women are not having screening mammograms. Use was not higher primarily because women did not realize that screening mammography tests for breast cancer in asymptomatic women. Primary care physicians are the main source of health education for screening mammography. The data suggest that public health programs to promote screening mammography should especially target primary care physicians and women with low incomes and education. Likewise, health care providers should ensure that their patients are referred to facilities that deliver high-quality mammography at low cost to make the procedure more accessible.

Breast cancer among black and white women in the 1980s. Changing patterns in the United States by race, age, and extent of disease

BACKGROUND

This national study of breast cancer incidence and mortality was conducted to determine whether patterns of change differ for black and white women, to evaluate patterns by extent of disease, and to determine whether recent patterns of breast cancer are consistent with results that one would expect due to increases in use of screening examinations by women.

METHODS

The study included 104,351 cases of in situ or invasive breast cancer diagnosed between 1983 and 1989 among women from the nine geographic areas participating in the National Cancer Institute Surveillance, Epidemiology, and End Results program. Breast cancer incidence patterns were examined by extent of disease for black and white women and by age at diagnosis.

RESULTS

Significant increases occurred in the incidence of all early-stage breast cancers. Concomitantly, significant decreases occurred in the incidence of the most advanced-stage breast cancers. Although both white and black women experienced significant increases in early-stage breast cancer, black women have substantially lower rates of the least extensive breast cancers.

CONCLUSIONS

These results strongly suggest that a major explanation for the increase in breast cancer incidence in the 1980s may well be the increased prevalence of breast cancer screening among women in the United States. They also suggest a consistent benefit of screening across all age groups from 40 to 49 years through 70 years and older.

Health care reform in the United States

The need for change in the system of health care delivery in the United States has finally emerged as a political issue alongside continuing budget deficits, a growing national debt, declining educational outcomes, and decreased competitiveness of American business in the global economy. The two most pressing health care problems at the present time are rapidly increasing costs and lack of access to the system. A more distant but potentially more recalcitrant problem is the ageing of our population. This paper outlines and discusses some of the options for reform which are currently under consideration in the United States.

How cost-effective is breast cancer screening in different EC countries?

Should the decision to start breast cancer screening in the Netherlands and in the U.K. be followed by other EC countries? This question has been addressed in an exploratory analysis of the differences in cost-effectiveness of breast cancer screening in Spain, France, the U.K. and the Netherlands. A detailed cost-effectiveness analysis of breast cancer screening in the Netherlands has been used as the starting point. Country specific data on incidence, mortality, demography, screening organisation and price levels in health care have been used to predict the costs and effects of nationwide screening programmes, in which women aged 50-70 are invited for 2-yearly mammographic screening. The relative effect of screening is highest in the U.K. (16.55 life-years gained per 1000 screens) and lowest in Spain (8.23 life-years gained per 1000 screens). The cost per screen is highest in Spain (38 pounds) and lowest in the U.K. (18 pounds). In comparison with the yearly health expenditures per capita, the cost per life-year gained is 2.8 times higher in the Netherlands, 3.1 times higher in the U.K., 6.5 times higher in France and 20.6 times higher in Spain. These marked differences show that no uniform policy recommendations for breast cancer screening can be made for all countries of the EC.

Screening mammography

Screening mammography can reduce mortality from breast cancer and is the only means of detecting nonpalpable cancers that are often more curable. Based on this, guidelines have evolved but compliance with them has been slow. Reservations are based on yield-cost-benefit-harm considerations, but uniformed and/or disadvantaged women and reluctance if not resistance to screening mammography by primary care physicians are major problems. The challenges are to overcome these obstacles and to obtain sufficient competent personnel and facilities to make reproducibly optimum screening mammography, which is accurately interpreted, widely available to all eligible women at the lowest possible cost.