When to Get a Screening Mammogram
How often and when to start routine mammograms is a matter of debate.
Changing the Story continued...
It was widely reported, however, that the USPSTF was against screening entirely for women with an average risk of breast cancer between the ages of 40 to 49. That wasn't the case, says Diana Petitti, MD, professor of biomedical informatics at Arizona State University and vice chair of the 2009 USPSTF committee.
The actual recommendation was not communicated well, according to Petitti. "The decision about the age to start being screened at 40, 42, 44, 48, should be one that was more individualized," she says, rather than a woman's 40th birthday triggering an automatic authorization slip from her doctor to get a mammogram.
The USPSTF's other recommendations included biannual, rather than annual, mammograms for women ages 50-74. And there is insufficient evidence, the task force said at the time, to accurately assess the benefits and drawbacks of regular mammograms for women older than 75.
The Trouble With Statistics
The argument over when women should start breast cancer screening stems from a disagreement about the process the task force used to reach its conclusions. It relied on a sophisticated computer model rather than real-life, clinical, randomized studies to determine how many breast cancers are caught and treated in women ages 40-49.
Lichtenfeld says that the conclusions reached by multiple institutions using the same model were different. "So the reliability of that model to make a clinical decision, particularly when we have data from actual studies, we felt was not quite ready for prime time," he says.
Phil Evans, MD, representative of the Society of Breast Imaging and director of the Center for Breast Care at the University of Texas Southwestern Medical Center, concurs with Lichtenfeld.
"One of the assumptions the task force made was the reduction of mortality in between the ages of 40 and 49 was 15%, and we know from real-life studies ... that the number is closer to 30%, twice what they used in their modeling. That's a huge difference in the number of lives saved," he says.
"The task force did acknowledge at the time that mammography did reduce deaths for women between ages 40-49, Lichtenfeld says. "However, we said then, and I think it's fair to repeat today, that the task force didn't feel enough lives were saved for women in that age group, because breast cancer is more common as you get older."
The American Cancer Society, Lichtenfeld says, disagrees and continues to recommend routine screening mammograms for women age 40 and older.