Breast cancer: The earlier the screening, the better

A new study questions the controversial US Preventative Service Task Force recommendations for breast cancer screening, with data that shows starting at a younger age and screening more frequently will result in more lives saved.

The study analysed 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 Centre. 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 Modelling Network. This is the same modelling data the task force considered. The authors compared task force guidelines to American Cancer Society guidelines.

71% more lives saved with annual screening beginning at 40

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

The difference between these two screening strategies comes down to 71% 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 emphasised 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.

Task force erred

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 be asked back for more tests once every 12 years and will undergo a false-positive biopsy once every 149 years.

"The task force overemphasised 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% of breast cancer deaths are averted in women who get regular screening mammography. Our modelling results agree completely with these screening program results in terms of the large number of women lives saved by regular screening mammography."

Source: University of Colorado School of Medicine