Yet most of the women received only five exams during the 10-year-time period. The study appears today on the website of Cancer, a journal of the American Cancer Society.
''I think it's very likely this is a widespread phenomenon in America, the failure of women to return promptly to get mammograms," said James Michaelson, study author and assistant professor of pathology at the hospital and Harvard Medical School. ''Prompt annual return is really important to get the maximum life-sparing benefit of screening mammography."
Mammograms remain the best method for detecting breast cancer when it's most treatable, the Institute of Medicine said earlier this month.
Women who screen annually and are diagnosed with breast cancer die from the disease half as often as those who do not get annual exams, Michaelson said.
''We have a problem in mammography in this country -- the message still hasn't gotten out that mammography will save lives," said Dr. Herman Kattlove, a medical editor with the American Cancer Society who was not involved with the study.
Poor women, those without health insurance and those from nonwhite racial and ethnic groups had particularly low rates of receiving mammograms, but no group of women used mammography often, Michaelson said.
''That tells me it's the system that is failing, that is not helping women," Michaelson said. ''We simply don't do a good enough job of sending reminders."
A worsening shortage of providers has also affected women's access to mammograms. In parts of the country, long waits for breast X-rays are common. That's because fewer radiologists are specializing in breast imaging because of long hours, low pay, heavy regulation, and fear of lawsuits.
''Mammography is the stepchild of medical care. There's just not much incentive to do it -- we're beginning to face a decline in access to mammography," Kattlove said.
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