Only half of eligible women in the United States are getting their annual mammograms, even if they have insurance to pay for the procedure, according to data presented at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium.

Last year the U.S. Preventive Services Task Force, an independent panel of non-federal experts in prevention and evidence-based medicine, recommended that the age of first mammogram be lifted from 40 to 50 years of age, at which biennial mammography begins, and caused a public outcry. To date, no major insurance company or other organization has acted on that recommendation.

"Women reacted strongly to that recommendation with protests about their right to have an annual mammogram that should not be taken away," said Milayna Subar, M.D., vice president and national practice leader for oncology at Medco Health Solutions, Inc. in N.J. "Interestingly though, we found that a large percentage of women do not get regular mammograms."

Subar and colleagues reviewed medical claims between January 2006 and December 2009 from a database of more than 12 million people. All participating women had either employer-provided insurance or Medicare.

Among those who were 40 to 85 years of age, only 50 percent had a mammogram in any given year and only 60 percent had two or more mammograms over four years. Average annual mammography rates were 47 percent for women aged 40 to 49 years, 54 percent for women aged 50 to 64 years and 45 percent for women aged 65 years and older.

The researchers did not examine reasons as to why the women were not getting mammograms, but several theories exist, according to Subar. Among these theories: discomfort from the test, lack of available screening centers, general non-compliance or denial.