Quality of Mammography Facilities Serving Vulnerable Women

Institution: University of California, San Francisco
Investigator(s): L. Elizabeth Goldman, M.D. -
Award Cycle: 2008 (Cycle 14) Grant #: 14IB-0062 Award: $150,000
Award Type: IDEA
Research Priorities
Community Impact of Breast Cancer>Disparities: eliminating the unequal burden of breast cancer

Initial Award Abstract (2008)

Women from vulnerable populations, such as those who live in rural areas, have low income, limited education, and racial and ethnic minorities, are more likely to die from or be harmed by breast cancer. These disparities result, in part, from differences in access to efficient and effective diagnosis. Mammography, the mainstay of breast cancer diagnosis, decreases mortality, yet there remains significant variability in quality of mammography readings among mammography facilities. Breast cancer advocates promote improving access to high quality care for all breast cancer patients, regardless of their race or ethnicity, income, education, location of residence. However, there is little information as to whether the quality of mammography facilities where vulnerable women are diagnosed with breast cancer differ from other facilities, or, if differences exist, what path advocates should take to improve the quality of mammograms accessible to these women.

We will investigate the underlying mechanisms perpetuating disparities in breast cancer screening and detection. Specifically, we will evaluate whether there are differences in quality of diagnostic examinations performed by mammography facilities serving vulnerable women and whether there are any areas where policy interventions at the facility level could decrease differences in quality. This analysis will use 1998-2004 data from the seven Breast Cancer Surveillance Consortium (BCSC) registries. We propose to evaluate whether “wait time” for scheduled diagnostic mammography varies by facility and whether the staffing and availability of same-day readings explain differences in quality. We will use four criteria to classify facilities serving medically vulnerable populations: educational attainment, racial/ethnic minority, household income, and rural/urban residence.

This project takes a novel perspective to disparities in breast cancer diagnosis by considering the effect of the overall quality of the facility that vulnerable patients use. This study also will investigate the facility level characteristics that could account for differences, which will permit policy-makers and advocates to focus quality improvement and public reporting efforts on these target areas.

Final Report (2010)

Note: Dr Goldman received a 2-yr renewal grants to continue this research Accuracy in diagnostic mammography varies across nationally across facilities, in part, because of differences in radiologists' experience, equipment, practice patterns, and patient populations undergoing diagnostic mammography. Disparities in cancer care and outcomes for vulnerable women are well established. However, it was unknown whether the accuracy of diagnostic mammography differs between facilities serving vulnerable women and facilities serving non-vulnerable women, and whether differences in accuracy are associated with facility characteristics such as affiliation with an academic center.

We analyzed mammography registry data from 7 states participating in the Breast Cancer Surveillance Consortium (BCSC) during 1999-2005 and compared the sensitivity, false positive rates, and cancer detection rates of diagnostic mammography. We categorized facilities as vulnerable based on percentage of mammographies performed on women who were racial/ethnic minorities, lived in a rural area, or had less than a high school education or a limited household income. We then linked the registry data to the BCSC Facility Survey to evaluate whether facility characteristics such as for-profit ownership, affiliation with a teaching facility, or on-site avail ability of ultrasound and biopsies could explain why vulnerable facilities had higher false positives. Initially, we intended to use a survey of 45 mammography facilities in the BCSC, but determined that only 3 of these facilities served a high proportion of vulnerable women. To overcome this challenge, we linked the BCSC registry data to a BCSC facility survey of the entire group of mammography facilities.

We found that the facilities serving vulnerable women were more likely to determine that women need further diagnostic work-up unnecessarily (i.e. higher false positive rates) than facilities serving non-vulnerable women, but did not find differences in the likelihood of missing cancers (i.e. similar sensitivity). While the availability of ultrasound and biopsy services on-site were associated with greater odds of a false positive, the availability of these diagnostic services on-site did not account for the higher false positive rates at facilities serving vulnerable women nor did affiliation with an academic center or profit status.

We would like to further understand whether our findings that facilities serving vulnerable women have higher false positive rates is a result of fewer recommended biopsies occurring or significantly delayed biopsies so as to inform interventions to improve the quality of diagnostic mammography at these facilities.

Symposium Abstract (2010)

L. Elizabeth Goldman, M.D., M.C.R. (PI)1, Rod Walker, M.S.2, Diana L. Miglioretti2,3, Ph.D., Rebecca Smith-Bindman, M.D.4, Karla Kerlikowske, M.D.1
1 Department of Internal Medicine, University of California, San Francisco, San Francisco, CA
2 Biostatistics Unit, Group Health Research Institute, Seattle, WA
3 Department of Biostatistics, University of Washington, Seattle, WA
4 Department of Radiology, University of California, San Francisco, San Francisco, CA

Background: Breast cancer missed on diagnostic mammography may contribute to delayed diagnoses, while false-positive results may lead to unnecessary invasive procedures. Whether accuracy of diagnostic mammography at facilities serving vulnerable women differs from other facilities is unknown.

Objective: To compare the diagnostic accuracy of diagnostic mammography at facilities serving vulnerable women to those serving non-vulnerable women.

Design: We examined 168,251 diagnostic mammograms performed at Breast Cancer Surveillance Consortium facilities from 1999-2005. We used hierarchical logistic regression to compare sensitivity, false positive rates, and cancer detection rates.

Subjects: Women ages 40-80 years undergoing diagnostic mammography to evaluate an abnormal screening mammogram or breast problem.

Measures: Facilities were characterized according to the populations served based on the proportion of mammograms performed on women with lower educational attainment, racial/ethnic minorities, limited household income, or rural residences.

Results: Sensitivity of diagnostic mammography did not vary significantly across vulnerability groups adjusted for patient-level characteristics, but false-positive rates among diagnostic mammograms to evaluate a breast problem were higher at facilities serving vulnerable women: lower educational attainment (odds ratio (OR) 1.39; 95% confidence interval (CI) 1.08, 1.79); racial/ethnic minorities (OR 1.32; 95% CI 0.98, 1.76); limited income (OR 1.34; 95% CI 1.08, 1.66), and rural residence (OR 1.55; 95% CI 1.27, 1.88).

Conclusions: Diagnostic mammography to evaluate a breast problem at facilities serving vulnerable women has higher false positive rates than at facilities serving non-vulnerable women. This may reflect concern about incomplete follow-up after abnormal diagnostic mammography and/or high cancer prevalence in vulnerable women.

Implications: Interventions to improve diagnostic mammography accuracy at facilities serving vulnerable women may reduce unnecessary invasive procedures.

Accuracy of diagnostic mammography at facilities serving vulnerable women.
Periodical:Medical Care
Index Medicus:
Authors: Goldman LE, Walker R, Miglioretti DL, Smith-Bindman R, Kerlikowske K
Yr: 2011 Vol: 49 Nbr: 1 Abs: Pg:67-75