Abstract PR07: Disparities in time to diagnostic follow up after screening mammography

Background: Screening mammography has been associated with as much as a 20% reduction in breast cancer mortality among women ages 40-74 years. An understudied dimension of screening that may impact mortality is time until follow-up after a positive mammogram. The primary objective of this study is to compare by race and insurance type the time to follow up after a positive screening mammogram.

Methods: We use 1995-2010 data from the Carolina Mammography Registry (CMR), a population-based registry. The data are collected from women and the radiologist interpreting the mammogram and include patient demographics, patient risk factors (breast density, family history of breast cancer, menopausal status), the imaging examination performed, the reason for the visit, the radiologists' assessment and recommendation for follow-up. The data are linked with cancer outcomes from the North Carolina Central Cancer Registry and abstracted pathology reports. In this study we included women ages 18 and older with a positive screening mammogram. A mammogram was positive if the Breast Imaging Reporting and Data System (BI-RADS) score was 0, 4, 5, or 3 with recommendation for biopsy evaluation. We defined time to diagnostic follow-up as number of days from the initial positive screening mammogram until the date of the first follow-up event (additional breast imaging or biopsy) before a cancer diagnosis or benign pathology result. We describe time to diagnostic follow-up for the cohort, by racial/ethnic status, and by insurance type (Medicare only, Medicaid, Medicare and Medicaid, Medicare and other insurer, all other insurers including private insurers, and No Insurance). We use Cox proportional hazards to estimate hazard ratios (HR) and 95% confidence intervals (CI) to evaluate the association between insurance type and diagnostic follow-up adjusting for race, patient residence, education, and imaging practice.

Results: Of 97,304 positive screening mammograms included in the study, the majority of the sample was White, non-Hispanic (80%), Black, non-Hispanic (13%), Hispanic (1%), Multi-racial/other (1%), and Native American (<1%). About 64% of the population reported insurance type as any other insurer including private insurers such as those offering HMO, PPO, or veterans benefit plans. About 18% of the study population reported having Medicare with another form of insurance, followed by Medicare alone (7%), Medicaid (3%), Medicaid with Medicare (3%), No insurance (2%). Median time until diagnostic follow-up after a positive screening mammogram for the study population was 11 days. White non-Hispanics and Hispanics experienced a median follow-up of 11 days while Native Americans experienced a median follow-up of 16 days. Black and Asian women experienced median follow-up of 9 days. Those reporting Medicare experienced a median follow-up of 14 days while those reporting Medicaid experienced median follow-up of 8 days (p<0001). Those reporting any other insurer including private insurance experienced median follow-up of 8.5 days (p<0001). The hazard of diagnostic follow-up for those with Medicare with another form of insurance is 1.5 times the rate of those reporting all other insurers, controlling for other covariates in the model (95% CI 1.40-1.61). Women reporting Medicare only experience diagnostic follow-up at 1.2 times the rate of those reporting all other insurers (95% CI 1.13-1.34). Uninsured women in this group were 29% less likely to have diagnostic follow-up (HR 0.71 95% CI: 0.61-0.83).

Discussion: In this breast cancer screening population women reporting Medicare alone or with supplemental insurance have increased hazard of diagnostic time until follow-up after a positive mammogram when compared to other women. The study may have a positive impact on maximizing the benefits of cancer screening and reducing disparities in breast cancer care.

This abstract was also presented as Poster B72.

Citation Format: Danielle Durham, Whitney Robinson, Sheila Lee, Stephanie Wheeler, James Bowling, Louise Henderson. Disparities in time to diagnostic follow up after screening mammography. [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 PR07.