Yearly mammograms from age 40 save 71 percent more lives, study shows

The study analyzed the same data looked at by the task force, which issued its guidelines on mammography screening in November 2009. The study authors compared the task force's recommendations for screening every other year in women 50-74 to American Cancer Society guidelines of screening every year in women 40-84.

The study was conducted by R. Edward Hendrick, Ph.D., clinical professor of radiology at the University of Colorado School of Medicine, and Mark Helvie, M.D., director of breast imaging at the University of Michigan Comprehensive Cancer Center. It appears in the February issue of the American Journal of Roentgenology.

Hendrick and Helvie used six model scenarios of screening mammography created by the Cancer Intervention and Surveillance Modeling Network. This is the same modeling data the task force considered. The authors compared task force guidelines to American Cancer Society guidelines.

They found that if women begin yearly mammograms at age 40, it reduces breast cancer deaths by 40 percent. When screening begins at 50 and occurs every other year, it reduces breast cancer deaths 23 percent.

The difference between these two screening strategies comes down to 71 percent more lives saved with yearly screening beginning at 40.

"Task force guidelines have created confusion among women, leading some to forego mammography altogether. Mammography is one of the few screening tools that has been proven to save lives and our analysis shows that for maximum survival, annual screening beginning at 40 is best. This data gives women more information to make an informed choice about the screening schedule that's best for them," says Helvie, professor of radiology at the U-M Medical School.

As part of their recommendation, the task force emphasized the potential harms mammography can cause -- including pain during the screening exam and anxiety from false-positives, which can lead to additional imaging or biopsy.

The study authors found that on average women ages 40-49 who are screened annually will have a false-positive mammogram once every 10 years. They will get asked back for more tests once every 12 years and will undergo a false-positive biopsy once every 149 years.

"The task force overemphasized potential harms of screening mammography, while ignoring the proven statistically significant benefit of annual screening mammography starting at age 40," Hendrick says. "In addition, the panel ignored more recent data from screening programs in Sweden and Canada showing that 40 percent of breast cancer deaths are averted in women who get regular screening mammography. Our modeling results agree completely with these screening program results in terms of the large number of women lives saved by regular screening mammography."

Breast cancer statistics:

209,060 Americans will be diagnosed with breast cancer this year and 40,230 will die from the disease, according to the American Cancer Society.