Potential overuse of screening mammography and its association with access to primary care.

BACKGROUND: Cancer screening in individuals with limited life expectancy increases the risk of diagnosis and treatment of cancer that otherwise would not have become clinically apparent.
OBJECTIVE: To estimate screening mammography use in women with limited life expectancy, its geographic variation, and association with access to primary care and mammographic resources.
METHODS: We assessed screening mammography use in 2008-2009 in 106,737 women aged 66 years or older with an estimated life expectancy of <7 years using a 5% national sample of Medicare beneficiaries. Descriptive statistics were used to estimate the screening mammography utilization, by access to primary care.
RESULTS: Among women with a life expectancy of <7 years, 28.5% received screening mammography during 2008-2009. The screening rates were 34.6% versus 20.5% for women with and without an identifiable primary care physician, respectively. The screening rates were higher among women who saw >1 generalist physician and who had more visits to generalist physicians. There was substantial geographic variation across the United States, with an average rate of 39.5% in the hospital referral regions (HRRs) in the top decile of screening versus 19.5% in the HRRs in the bottom decile. The screening rates were higher among HRRs with more primary care physicians (r=0.14, P=0.02), mammography facilities (r=0.12, P=0.04), and radiologists (r=0.22, P<0.001).
CONCLUSIONS: Substantial proportions of women with limited life expectancy receive screening mammography. Results presented sound a cautionary note that greater access to primary care and mammographic resources is also associated with higher overuse.