New study urges earlier mammograms; some experts not convinced
Even as a new Cancer study reignites the debate over the ideal age at which to begin mammogram screenings for breast cancer, City of Hope experts are urging women not to settle for a one-size-fits-all approach.
The Harvard University study, published Monday, started with data on 7,301 women diagnosed with breast cancer at one Boston hospital. Of the 609 women who died, 65 percent either had never had a mammogram or had not had a mammogram within two years of their diagnosis, researchers found. Half of the deaths occurred in women under age 50.
The American Cancer Society maintains a recommendation that yearly mammograms should begin at age 40, but the U.S. Preventive Services Task Force has recommended that women receive mammograms from ages 50 to 74, and then only every two years. That recommendation was based on data showing that earlier tests do more harm than good, leading to many false-positives that often cause additional expense, unnecessary anxiety and needless follow-up procedures.
The authors of the new study said their findings suggest that screening guidelines should encourage earlier, regular mammograms for all women. Other experts, including those at City of Hope, aren’t so sure.
Joanne Mortimer, M.D., director of the Women’s Cancers Program at City of Hope, points out that the study was not a randomized clinical trial – a gold standard for research. Data from those trials does not support across-the-board screening for every woman beginning at age 40, she said.
Further, the key to preventing breast cancer deaths and catching the disease as early as possible, Mortimer said, is assessing women for their individual risk, then screening appropriately.
“Some organizations have left the screening age at 40 because it’s such a contentious issue. It’s more about emotion than data,” Mortimer said. “Risk assessment is really very critical. We harp on individualized health care, and that means understanding each woman’s risk. At low risk, don’t expose them to radiation unnecessarily. Women at very high risk, by all means they may need mammograms and they may also need an MRI.”
Younger women who develop breast cancer tend to have a more aggressive form of the disease – which is actually an argument against beginning routine mammograms earlier, Mortimer pointed out. Such cancers form and progress quickly – often in less than a year or two, meaning that mammograms wouldn’t necessarily catch them and might, instead, create a false sense of security. Again, Mortimer said, risk assessment is crucial.
High-risk patients typically receive screenings every six months, alternating between an MRI and mammogram. About 5 to 10 percent of breast cancer cases are considered hereditary, and the most common known cause of hereditary breast cancer is a mutation in the BRCA1 and BRCA2 genes. Those with the gene mutation may be at an 80 percent risk of developing breast cancer. These cancers tend to occur in younger women and more often affect both breasts than cancers in women who do not have the mutation.
Other women who may be at high risk include those who have been exposed to chest radiation or who have had a prior cancer. Even women who have tested negative for one of the known cancer mutations, but have a strong family history of breast cancer, might also be high risk.
“There are women whose family histories are incredibly strong, but we haven’t identified a gene yet,” Mortimer said. “Those women should be aggressively screened as well.”
Mammograms are a valuable diagnostic tool, but like all cancer screening tools, they must be used appropriately. The most beneficial approach is one that takes into account a woman’s individual risk factors and needs, Mortimer said.
“Getting an annual mammogram does deliver radiation,” she said. “If you don’t need to get it, why expose yourself?”