Skip to content

    Breast Cancer Health Center

    Font Size

    New Clues on Breast Cancer Decline

    Increases and Drops in Breast Cancer Rates Tied to HRT Use

    Does HRT Cause Breast Cancer? continued...

    One theory is that menopausal hormone therapy fuels the progression of already existing precancerous cells within the breast, just as antiestrogen treatments like tamoxifen slow the growth of existing ER+ tumors.

    “We have known that these cancers respond to hormones used for treatment,” Glass says. “What we didn’t know was that the use of hormones for other reasons may encourage the growth of these cancers.

    So does menopausal hormone therapy actually cause breast cancers or just promote their growth?

    The answer isn’t clear, but University of Texas M.D. Anderson Cancer Center professor of biostatistics Donald A Berry, PhD, says the latter scenario is more likely.

    In an editorial accompanying the study, Berry noted that if HRT caused ER+ breast cancers, the decline in cancers as women stopped the therapy would be far more gradual than what was seen in 2003.

    “It is conceivable that some of these cancers would never show up without this fuel, but we don’t know that,” he tells WebMD.

    Another unanswered question, Berry says, is whether the recent decline in breast cancer incidence will translate into a large drop in cancer deaths.

    Since the drop was largely confined to more highly treatable hormone-sensitive breast cancers, he says it may not.

    “It is quite possible and indeed likely, that the [decline] we are seeing will have minimal if any effect on breast cancer mortality,” he says.

    The decision to use HRT is made in collaboration with your doctor and is based on risk factors, such as personal medical history and family history and benefits. If the decision to use HRT for menopausal symptoms is made, most menopause groups now recommend using HRT in the lowest effective dosage for the shortest time possible to treat hot flashes and other menopause symptoms.

    • If you’re in the early stages of breast cancer and need support, you can find other women like you on WebMD's Breast Cancer: Friend to Friend message board.

    1 | 2

    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