(RxWiki News) False-positives are a potential downside of breast cancer screening, and one that the US Preventive Services Task Force (USPSTF) says patients and their doctors should consider.
False-positives occur when a mammogram finds something that looks like cancer, but it turns out not to be. This can cause a patient unnecessary distress and lead to sometimes costly additional testing.
A new study found that false-positive results and recommendations for additional imaging were more common among younger women (ages 40 to 49) and those with certain risk factors for breast cancer. False-negative results and biopsy recommendations were less common.
These findings were used to inform the updated breast cancer screening recommendations from the USPSTF. The agency now recommends that the decision to begin screening for breast cancer be an individual one — taking into account a woman's health history, preferences, and how she values the potential benefits and harms of screening.
"Ultimately, these recommendations support a range of choices for women on when to initiate screening — from beginning regular mammograms at age 40 or at some point during their 40s or waiting until age 50, when the likelihood of benefit is greater," wrote Albert L. Siu, MD, and colleagues, on behalf of the USPSTF, in an editorial about the new recommendations.
For this study, a team of researchers led by Heidi D. Nelson, MD, a research professor at Oregon Health & Science University, looked at 405,191 women ages 40 to 89 screened with mammography between 2003 and 2011.
A total of 2,963 women were diagnosed with invasive breast cancer or ductal carcinoma in situ (DCIS) within one year of screening. DCIS is a type of noninvasive breast cancer that starts in the milk ducts.
Dr. Nelson and team found that false-positive results and additional imaging recommendations were highest among younger women. These rates decreased with age.
Rates of false-negative results and biopsy recommendations were generally low and did not differ greatly with age.
Some risk factors, such as a family history of breast cancer, past biopsy, dense breasts and low body mass index (BMI) for younger women, were also tied to a higher risk of false-positive results.
The study and editorial were published Jan. 11 in the journal Annals of Internal Medicine.
The USPSTF funded this research. No conflicts of interest were disclosed.