Research by Dr. Nancy Breen of the National Cancer Institute, among others, shows the mammography rate fell by as much as 4 percent nationwide between 2000 and 2005.
The report's authors call that drop "significant" and say theirs is the first study to detect that the decline is nationwide.
The study appears in the June issue of the journal Cancer of the American Cancer Society.
Some of the sharpest declines were seen among women who previously reported high screening rates — women between 50- and 64-years-old, and women in higher socioeconomic levels.
Dr. Breen and her co-authors noted that the dip in screening rates coincides with a fall in the reported cases of breast cancer, and say they "are concerned that some of the observed decline in incidence (of breast cancer) may be due in part to the leveling-off and reduction in mammography rates."
On The Early Show Monday, Dr. Michele Blackwood, a breast cancer surgeon and medical director of the Connie Dwyer Breast Center (www.cathedralhealth.org/connie_dwyer.html) in Newark, N.J., called the possible trend "scary."
She told co-anchor Julie Chen the drop among women 50-64, "the baby boomers, the well-educated, the ones with the most insurance" is "shocking." Their decrease is seven percent.
One factor, Blackwood noted, may be the sudden drop in the use of hormone replacement therapy for the symptoms of menopause, after a 2002 study tied HRT to an increased risk of breast cancer and heart disease. Many women in that age group had gotten into the habit of going to their doctors for hormone replacement therapy, and getting annual mammograms as part of that process. When women stopped visiting their doctors for HRT prescriptions, they may not have continued going just for mammograms.
Another possible factor is the closing of roughly 10 percent of mammography centers in the U.S. due to lower insurance reimbursement rates for the procedure as well as a rise in lawsuits.
Some complacency may also be at work here, Blackwood said: The medical community has done such a good job of treating breast cancer and making it less of a death sentence that certain women may have lost their fear of the disease. Of course, it's early detection that allows for more successful treatment.
"Breast cancer can be cured if it's caught in an early stage. The way to do that is to have an annual mammogram," Blackwood stressed. "If you're in your 40s or 50s, you have 25 to 40 percent less chance of dying from breast cancer if you have an annual screening mammogram."
Blackwood offered suggestions on how women older than 40 can remember to get their annual mammograms. One was to tie it to an important date, such as your birthday or that of someone in your family. Also, go for the test with someone you know: "Bring them with you. Make a day of it! Go to lunch." And pamper yourself afterwards, with something simple, such as having your nails done.
"You shouldn't be dreading" having a mammogram, Blackwood said. "You're doing something good for yourself" that day.
As for women who don't have their own doctor or health insurance, Blackwood said, "Actually, there are many programs around the country sponsored at the state, county or city level where women can go for convenient mammograms that are free or very inexpensive. Women should call their local health authorities to find out how to obtain those mammograms."
So, she concluded, there's no excuse not to get a mammogram!
"If I told you I had a cheap way to spend just a few minutes and help yourself prevent a serious disease, wouldn't you take advantage of it? That's what a mammogram is. It's as simple as that."