Skip to content

    Breast Cancer Health Center

    Font Size

    False-Positive Mammograms Are Low

    Norwegian Study: 1 in 5 Women Over Age 50 Affected In 20 Years
    WebMD Health News

    Aug. 23, 2004 -- Almost all women deal with anxiety after having a mammogram. Many are concerned about the risk of being told their results are abnormal.

    Researchers now estimate that about one in five women who start getting mammograms between age 50 and 51 will get false-positive results during the next 20 years of screening.

    While acknowledging the stress that may come from a false-positive mammogram, the rate seems to be "acceptable," given mammography's benefits, write the researchers in the online edition of the journal CANCER.

    Solveig Hofvind, MSc, and colleagues from the Cancer Registry of Norway studied data from the Norwegian Breast Cancer Screening Program.

    In Norway, every woman aged 50-69 is sent a letter inviting her to get a mammogram every other year. More than 83,000 women take that opportunity to have a screening mammogram done; information from their tests is then entered into the Norwegian Breast Cancer Screening Program data base.

    A screening mammogram is a test to detect breast cancer changes in women who have no obvious signs of breast cancer. Early detection of breast cancer improves survival and reduces the number of deaths from the cancer.

    These screening tests can, however, result in a false-positive mammogram reading -- a mammogram read as having some abnormality when in fact no cancer is actual present. This has been reported to be one disadvantage of many breast cancer screening programs. These false positive results can cause significant distress to many women.

    In this newly published study researchers estimate the risk of a false-positive mammogram during a 20-year period in women who have screening mammograms starting at age 50 or 51.

    The vast majority of women who start getting mammograms in their early 50s never have that problem, according to the Norwegian study. They find that the rate of a false-positive test was 21%, or approximately one in five women.

    Even fewer women, 1%-4%, would have additional procedures resulting from the false-positive screening mammogram. These additional procedures include needle biopsy or other more invasive surgical procedures.

    Although all abnormal mammograms should be followed up with additional testing (a diagnostic mammogram, ultrasound, and/or biopsy), most abnormalities turn out not to be cancer.

    About seven out of 10 recalled women in the study had a follow-up mammography or ultrasound.

    Women should be told how much -- or little -- risk they may have of a false-positive mammogram, say the researchers, who call for further studies on the topic.

    SOURCE: Hofvind, S. CANCER (online edition), Aug. 23, 2004.

    Today on WebMD

    Breast Cancer Overview
    From mammograms to living after treatment.
    Dealing with breast cancer
    Get answers to your questions.
    woman having mammogram
    The 3 latest tips to know.
    woman undergoing breast cancer test
    Most abnormalities aren’t breast cancer.
    Resolved To Quit Smoking
    Breast Cancer Treatments Improving
    Woman getting mammogram
    Screening Tests for Women
    serious woman
    Pink badge on woman chest to support breat cancer
    what is your cancer risk
    breast cancer survivors