When to Get a Screening Mammogram
How often and when to start routine mammograms is a matter of debate.
The Harm of Too Much Testing
One of the central issues upon which the USPSTF based its recommendations had to do with the harm that can come from mammography testing: psychological harm, unnecessary imaging tests and biopsies, and false-positive mammogram results in which the patient is told there could be cancer, when in fact none exists. False-positive results are more common for women aged 40 to 49 than for older women.
"They were saying they felt the risk of harm of having extra procedures outweighed the benefit from saving lives, " Lichtenfeld says of the Task Force's reasoning to delay mammography.
The fact is that as women age, false positive mammography results decline. That's mainly because the density of a woman's breasts tends to decrease with age, making it easier to find cancer.
"Any given test that is a positive is more likely to be [truly] positive as women get older," Petitti says. A woman in her 40s asked to come back for follow-up tests because of a positive mammography has a 1 in 10 chance of actually having cancer.
But experts say that women understand mammography has limitations and still want to be screened for breast cancer.
"Most of the women you talk to would much rather go through that process and find something early than wait, " Evans says. "No one likes to have a false positive about anything, but it's part of what has to be done to find breast cancer early."
Both Evans and Lichtenfeld say annual screenings, rather than biannual, are especially important for women in their 40s because cancer tends to grow faster and more aggressively in younger women.
The government task force found a benefit to screening every other year because it reduced the number of false-positive results. "We asked what the risk-benefit ratio between one-year and two-year intervals was and the trade-off seemed to be favorable," Petitti says.
But Lichtenfeld takes issue with the task force's analysis. It looked at the number of women that need to be screened in order to save a life but not the number of years of life saved, he says. "If you find breast cancer in a young woman and save her life, she has more years of life ahead of her. Had they used that analysis, the [task force] may have come to a different conclusion," he says.