Women at average risk for breast cancer should begin annual mammograms at the age of 40, according to new guidelines issued by the largest organization of breast surgeons in the United States, the American Society of Breast Surgeons (ASBrS). These new recommendations are different from those offered by other medical organizations.
The American Cancer Society (ACS) updated its screening mammography guidelines in 2015, recommending women start having mammograms at age 45 rather than 40. The U.S. Preventive Services Task Force (USPSTF) changed its guidelines in 2016, moving the first suggested mammogram screening from 40 to 50 years of age.
About the New ASBrS Guidelines for Screening Mammography
The new ASBrS guidelines recommend that all women undergo a formal risk assessment by the age of 25. The guidelines recommend basing screening on those specific risk factors for women with an increased risk of breast cancer. In other words, women at high risk for breast cancer should undergo mammography early. The new guidelines suggest women with average risk begin annual screening at age 40.
ASBrS and USPSTF arrived at different conclusions for the recommended age of first-time mammograms because they used very different models to calculate risks and benefits. The USPSTF model looks at efficiency, while the ASBrS model looks at years gained.
"Routine screening for women age 40 to 49 has been unequivocally demonstrated to reduce mortality by 15%," said ASBrS president Dr. Walton Taylor in a news release. "However, today's USPSTF guidelines delay annual screening until age 50 because they are based on an 'efficiency' statistical model that also considers the impact of potential screening risks."
USPSTF's model includes the cost of screening, along with the probability of false-negative and false-positive results. False-negative results means cancer may go undetected, while false-positive results can lead to unnecessary medical procedures and needless anxiety.
The ASBrS used a 'life-years gained' model when establishing their guidelines. This model focuses solely on the demonstrated breast cancer survival benefits.
"The ASBrS prioritizes life," said Dr. Julie Margenthaler, who directs breast surgical services at the Siteman Cancer Center and is professor of surgery at Washington University School of Medicine in St. Louis.
Risk Assessment is an Essential Part of Accurate Screening
While the lower age for first mammograms is noteworthy, individual risk assessment is perhaps the most important aspect of the new guidelines. Other organizations recommend early screening for women at higher risk for breast cancer, of course, but the new ASBrS guidelines provide specific recommendations. For example, the new ASBrS guidelines recommend that women who have a 20 percent or greater risk of developing cancer should begin mammography screening, along with access to supplemental magnetic resonance imaging (MRI), beginning at age 35. The organization of surgeons recommends women with breast cancer-related genetic abnormalities start MRI imaging at the age of 25.
Mammography is not as easy or accurate in younger patients, but the benefits – especially in terms of years of life saved – are quite significant. "Many current guidelines will leave a subset of these women to die," Margenthaler explained.
Starting yearly screening at the age of 40, rather than performing less frequent or later screening, increases the odds of successful breast cancer treatment. By optimizing outcomes, early and frequent testing can also preserve quality of life for women.
"We are pleased that ASBrS has reaffirmed their support for this most sensible approach," said the chair of the American College of Radiology (ACR) Commission on Breast Imaging, Dr. Dana Smetherman. The new ASBrS guidelines are similar to ACR recommendations.
The one-size-fits-all approach to screening guidelines poses a problem because they do not account for individual risks. Assessing individual risks helps balance the benefits and harms of screening without risking women's lives. For example, the ASBrS guidelines recommend not using mammography on high-risk patients under the age of 30 who have genetic mutations or chest wall radiation in the past, but rather using annual screening with MRI until it is safe for them to undergo mammography screening.
At the other end of the life span, the ASBrS recommends halting screening mammography when a patient's life expectancy is less than 10 years. In comparison, the USPSTF has arbitrarily chosen the age of 74 to stop screening mammography. This poses problems because it does not accurately reflect the life expectancy of many women and it does not take into account the fact that the risk of breast cancer increase with age. The American Cancer Society's guidelines for stopping mammograms are vague, stating that mammograms should continue as long as the woman is in good health.
Annual screening for women of average risk who are over the age of 40 is essential to early diagnoses, which leads to optimal treatment outcomes.