Women at average risk for breast cancer should start regular annual screening using mammography at age 45 and transition to screening every two years starting at age 55, according to new guidelines from the American Cancer Society, published Oct. 20 in the Journal of the American Medical Association.
That’s a change from the old guideline that recommended screening start at age 40 and that exams continue on an annual basis for older women. Based on an evidence review, the American Cancer Society Guideline Development Group concluded there is a benefit from screening with mammography for women in their early 40s, according to a news release, but that risk is lower and harms, primarily from false positives, are somewhat greater for women ages 40-44 than for women in older age groups.
Cancers grow more slowly in post-menopausal women and biennial screening will give women 55 and older most of the benefit, with less risk, the development group review found.
Balancing benefits and harm
However, the guidelines recommend women ages 40-44 should have the option to begin screening early, and women 55 and older should have the opportunity to continue annual screens if they choose, according to the release. “These recommendations are made with the intent of maximizing reductions in breast cancer mortality and years of life saved while being attentive to the need to minimize harms associated with screening,” Kevin Oeffinger, MD, chairman of the breast cancer guideline panel and a family physician at Memorial Sloan Kettering Cancer Center, said in a news release. “The benefits, burdens and judgment about that balance differ depending on a woman’s age, health, values and preferences. These recommendations recognize and reflect those differences.”
The guideline recommends all women should become familiar with the potential benefits, limitations, and harms associated with breast cancer screening. It gives a strong recommendation that women with an average risk of breast cancer should undergo regular screening mammography starting at age 45.
It also gives qualified recommendations that women ages 45-54 should be screened annually; women 55 and older should transition to biennial screening but have the opportunity to continue screening annually; and that women 40-44 should have the opportunity to begin annual screening between the ages of 40 and 44.
Qualified recommendations indicate there is clear evidence of benefit of screening but less certainty about the balance of benefits and harms, or about patients’ values and preferences. “This guideline relies on the best evidence to offer new, more precise guidance taking into account a woman’s age, health and personal values and preferences,” Elizabeth Fontham, founding dean of the School of Public Health at LSU Health Sciences Center in New Orleans and chairwoman of the ACS Guideline Development Group, said in the release. “Though the evidence shows that there are some benefits from mammography screening starting at age 40, those benefits more clearly outweigh the harms from age 45 onward. Still, some women will choose to begin screening between age 40 and 44, both because they are concerned about their risk of breast cancer, either in general or because they are at higher risk, and are less concerned about the chances of experiencing a false positive findings. hose women should have the opportunity to start screening at 40 if they choose.”
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