Women aged 40 years and older presenting with an average risk of breast cancer are encouraged to begin biennial mammography screening at age 50, continuing through age 74, according to now-finalized recommendations from the U.S. Preventive Services Task Force (USPSTF) published in the Annals of Internal Medicine.
In an update of the 2009 recommendations, the USPSTF reviewed a wide range of evidence and comparative decision models, concluding that biennial mammography screening should begin in women aged 50 to 74 years. Women younger than age 50 may choose to begin mammography screening based on individual factors, and those placing a higher value on the potential benefits than potential harms may begin biennial screening between 40 and 49 years of age.
Current evidence remains insufficient regarding the benefits versus harms in women older than 75 years of age, as well as the benefits versus harms of digital breast tomosynthesis (DBT) as a primary screening method and of adjunctive screening using ultrasonography, magnetic resonance imaging (MRI), or other methods used in women identified as having dense breasts.
The updated USPSTF guidelines are as follows:
- The USPSTF concludes with moderate certainty that the net benefit of screening mammography in women aged 50 to 74 years is moderate.
- The USPSTF concludes with moderate certainty that the net benefit of screening mammography in the general population of women aged 40 to 49 years, while positive, is small.
- The USPSTF concludes that the evidence on mammography screening in women age 75 and older is insufficient, and the balance of benefits and harms cannot be determined.
- The USPSTF concludes that the evidence on DBT as a primary screening method for breast cancer is insufficient, and the balance of benefits and harms cannot be determined.
- The USPSTF concludes that the evidence on adjunctive screening for breast cancer using breast ultrasound, MRI, DBT, or other methods in women identified to have dense breasts on an otherwise negative screening mammogram is insufficient, and the balance of benefits and harms cannot be determined.
“The decision to start screening mammography in women prior to age 50 should be an individual one,” wrote Albert L Siu, MD, MSPH, professor of general internal medicine at Mount Sinai Hospital in New York City. “Women who place a higher value on the potential benefit than the potential harms may choose to begin biennial screening between the ages of 40 and 49 years.”
Dr. Siu and colleagues also noted that women aged 60 to 69 years stood to benefit the most from biennial screening and were most likely to avoid breast cancer death through mammography screening. However, women with a first-degree relative, including a parent, sibling, or child, who had a breast cancer diagnosis were considered at higher risk and thus would benefit from screening beginning at age 40. Additional clinically significant risks include women with a BRCA1 or BRCA2 gene mutation or other hereditary genetic syndromes, as well as women with a history of high-dose radiation therapy to the chest that occurred at a young age.
Meta-analysis results were achieved via a systemic evidence review of clinical trials. These results showed that, during a 10-year period, screening 10,0000 women aged 60 to 69 will result in 21 fewer breast cancer deaths. Screening 10,000 women aged 50 to 59 years will result in 8 fewer breast cancer deaths. Screening 10,000 women aged 40 to 49 years will result in 3 fewer breast cancer deaths.
“The most important harm of screening is the detection and treatment of invasive and noninvasive cancer that would never have been detected … in the absence of screening,” wrote Dr. Siu. “If overdiagnosis is the only explanation for the increase [in the rate of diagnosis of invasive plus noninvasive breast cancer], 1 in3 women diagnosed with breast cancer today is being treated for cancer that would never have been discovered or caused her health problems in the absence of screening.”
Dr. Siu concludes that trial data are still too limited; clinicians and patients should ultimately determine the best strategy for breast cancer screening on an individual basis.
- Siu AL, on behalf of the U.S. Preventive Services Task Force (USPSTF). Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2016; doi: 10.7326/M15-2286