The ACS have recommended new guidelines for breast cancer screening.
In the first major update since 2003, the American Cancer Society (ACS) recommend that women with an average risk of breast cancer undergo regular, annual screening mammography from age 45, but with the option of starting earlier; and women 55 years and older should screen every second year instead of annually, but with the option of continuing annually.
Breast cancer is the second cause of cancer death in US women, after lung cancer. It is estimated that in 2015, some 230,000 American women will be diagnosed with breast cancer, and 40,300 women will die from it.
Death from breast cancer has declined steadily since 1990, largely due to improvements in early detection and treatment. Early detection is considered essential to successful treatment of breast cancer.
Annual screening from 45-54 years
The new recommendations are based on findings from a number of studies into the balance of benefits and harms of screening, and they are designed for use in the context of a clinical encounter.
- In 2013, 65.7% of American women underwent breast cancer screening
- The highest percentage of women undergoing screening was 71% for ages 50-64
- 56.6% of women aged 75 and over were screened.
The guidelines are as follows:
- Optional annual screening for women aged 40-44
- Regular screening mammography from age 45
- Annual screening for Women aged 45-54
- Biennial screening for women aged 55 plus, with the option to continue screening annually
- Continued screening as long as the woman has good overall health and a life expectancy of 10 years or longer.
Clinical breast examination (CBE) is not recommended for breast cancer screening among average-risk women at any age, due to "the absence of clear evidence that CBE contributed significantly to breast cancer detection prior to or after age 40 years."
A woman with an average risk of developing breast cancer should discuss screening around the age of 40 years, and she should be provided with information about risk factors, risk reduction, and the benefits, limitations and harms associated with mammography screening.
Women are urged to be aware of and to discuss their family and medical history with a clinician, who should check from time to time whether a woman's risk factor profile has changed.
Potential downsides of screening
The negatives of screening include over-diagnosis and false positive results, which are common with mammograms. Both can lead to unnecessary interventions, such as biopsy, or invasive treatment of cancers that might not have developed if they had not been diagnosed.
The ACS recommendations aim to maximize reductions in breast cancer mortality and the number of years of life lost, while minimizing the associated harm that can be caused by screening.
They recognize that the balance of benefits and harms will sometimes be close, and that differing values and preferences will lead to varying decisions.
"The intention of this new guideline is to provide both guidance and flexibility for women about when to start and stop screening mammography and how frequently to be screened for breast cancer."
In a linked editorial, Dr. Nancy Keating, of Harvard Medical School, and Dr. Lydia Pace, of Brigham and Women's Hospital, both in Boston, MA, point to evidence that for average-risk women under 45, the harms of mammography screening probably outweigh the benefits, and that for those over 55, biennial mammography is likely to provide the best balance of benefits to harms.
They concur that for older women with life expectancies of less than 10 years, it is practical and consistent to stop screening, keeping in mind the increasing emphasis on functional versus chronologic age.
In contrast with the ACS, the US Preventive Services Task Force (USPSTF) guidelines recommend no routine screening from age 45-49, and only biennial screening from age 50-74. Dr. Keating and Dr. Pace call on clinicians to balance the recommendations of the ACS with evidence that younger women "experience a lower absolute benefit" from screening.
Medical News Today recently reported on the variation in treatment for breast cancer among different ethnic groups in the US.