Women with false-positive test results for breast cancer may want to remain vigilant with screening, as false-positive results could be associated with underlying pathology that may result in breast cancer, according to the results of a study published in the Journal of the National Cancer Institute.
A mammogram is an X-ray of the breast. Screening mammography is performed in a woman without breast symptoms in order to detect breast cancer at an early stage when it is most easily treated. Different groups of experts have reached different conclusions about when mammographic screening should begin and how often it should be performed. The U.S. Preventive Services Task Force recommends that routine screening of average-risk women begin at age 50 and be performed every two years. The American Cancer Society recommends annual screening beginning at age 40.
Although screening mammography can reduce the risk of death from breast cancer (due to early detection), disease screening in healthy individuals can also lead to false-positive test results. A false-positive result suggests that cancer may be present even though the person is actually cancer-free. False-positive results can lead to anxiety and unnecessary additional testing.
Women with false-positive mammography results are usually referred back for routine screening; however, it is unknown whether these women have a higher long-term risk for breast cancer compared to women who initially test negative.
In order to determine if women with false-positive mammography results have a higher risk of developing breast cancer than those who test negative, researchers from the University of Copenhagen evaluated data from a population-based mammography program in Copenhagen, Denmark from 1991-2005. They used the data to measure the risk of breast cancer and ductal carcinoma in situ (DCIS) in 58,003 women between the ages of 50-69 who had received false-positive test results.
The results indicated that women who had tested negative for breast cancer had an absolute cancer rate of 339 per 100,000 person-years at risk, whereas women had tested false-positive had an absolute rate of 583 per 100 000 person-years at risk. Six or more years after the test, the relative risk of breast cancer in women with false-positive results was statistically significantly higher than women who tested negative; however, those statistics lowered when new screening technology was introduced in the year 2000.
It’s important for women to discuss screening options with their physician in order to determine their optimal screening protocol for breast cancer. Based on the results of this study, women with false-positive mammography results may benefit from close monitoring and continued regular screening.
 Euler-Chelpin MV, Risor LM, Thorsted BL, et al. Risk of breast dancer after false-positive test results in screening mammography. Journal of the National Cancer Institute. Published early online April 5, 2012: doi: 10.1093/jnci/djs176
Posted April 13, 2012