Abstract B79: Trends in mammography quality benchmarks met over time: Moving beyond the Mammography Quality Standards Act to address breast cancer disparities
Authors: Tossas-Milligan Katherine Y. , Irizarry Bethliz , Murphy AnneMarie , Rauscher Garth H. 
Published: October 2015

Backround: In 2007, the Metropolitan Chicago Breast Cancer Taskforce (The Taskforce) was initiated to identify the reasons for an alarming Black/White breast cancer mortality gap in metropolitan Chicago and to propose solutions. One hypothesis raised was that unequal access to high quality breast cancer screening and treatment care may be a significant driver of Chicago's breast cancer disparity. While there is growing interest in the role of breast cancer screening quality in explaining black/white breast cancer mortality gap, there is no research to our knowledge assessing quality measures about the breast cancer screening processes within facilities across the state of Illinois. We summarize data and report trends on 11 breast cancer screening metrics from 3 years of mammography quality data surveillance for facilities in Illinois.

Methods: The Taskforce collected aggregate data on 11 breast cancer screening quality metrics for calendar years 2006, 2009, and 2011, including the number of screening mammograms that: received follow-up imaging within 30 days and 12 months; received a biopsy recommendation within 12 months of the screen; resulted in a biopsy recommendation within 12 months; resulted in a biopsy (following recommendation) within 60 days and 12 months of the screen, respectively. Finally, we requested the number of cancers diagnosed within 12 months of an abnormal screening mammogram and the number of these that were minimal and early stage cancers. Data were analyzed for the 32 facilities that submitted metrics across all 3 years. The change in the mean number of benchmarks met was estimated using linear regression using a generalized estimating equations approach with exchangeable correlation matrix and robust standard errors to account for clustering by site. At each time point 95% confidence intervals were estimated.

Results: Out of 11 possible metrics, the average number of benchmarks met by each facility for 2006, 2009 and 2011 was 4.88, 7.06 and 8.09, respectively. This represented a 0.65 increase in the overall mean number of benchmarks met by calendar year (95%CI=0.44, 0.75) (or an overall 1.61 increase in the overall mean number of benchmarks met per time point, 95%CI=1.16, 1.97). With respect to individual benchmarks, the proportion of facilities able to show that they met the benchmarks increased substantially between 2006 and 2011 for many benchmarks including cancer detection rate (0.66 to 0.91, p=0.008), proportion of breast cancers diagnosed as minimal (0.28 to 0.88, p=0.0000) and early stage (0.22 to 0.66, p=0.000). Other benchmarks remained unmet by a majority of facilities despite showing substantial improvement over time. These included timely imaging within 30 days of the screen (0.28 to 0.44, p=0.077), and timely biopsy within 60 days of the screen (0.13 to 0.42, p=0.002).

Discussion: The American College of Radiology recommends that facilities meet certain additional quality benchmarks above and beyond the audit requirements of the Mammography Quality Standards Act. These include measuring the proportion of abnormal screening mammograms, timeliness of follow-up, extent of screen-detection (i.e., cancer detection rate for screening mammograms), and ability to detect small and early stage tumors. To date, none of these recommendations have been incorporated into MQSA guidelines. The results of this quality improvement project show an overall improvement across time in the average number of quality benchmarks institutions can demonstrate that they meet. Much of this improvement likely stems from an increased ability to collect and report the data needed to construct these measures. Lack of timeliness of diagnostic imaging and biopsy services remain a clear shortcoming for many facilities.

Citation Format: Katherine Y. Tossas-Milligan, Bethliz Irizarry, AnneMarie Murphy, Garth H. Rauscher. Trends in mammography quality benchmarks met over time: Moving beyond the Mammography Quality Standards Act to address breast cancer disparities. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr B79.