Hormone therapy increases frequency of abnormal mammograms, breast biopsies

February 25, 2008

Combined hormone therapy appears to increase the risk that women will have abnormal mammograms and breast biopsies and may decrease the effectiveness of both methods for detecting breast cancer, according to a report in the February 25 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Hormone therapy use remains common among women beginning menopause, according to background information in the article. "For women with a uterus considering combined estrogen plus progestin use, identified breast cancer issues represent a concern," the authors write.

Rowan T. Chlebowski, M.D., Ph.D., of the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, and colleagues studied 16,608 post-menopausal women who participated in the Women's Health Initiative (WHI) clinical trial, beginning in 1993 through 1998. A total of 8,506 women were randomly assigned to receive a combination of estrogen (0.625 milligrams of conjugated equine estrogens per day) plus progesterone (2.5 milligrams of medroxyprogesterone acetate per day), while 8,102 took a placebo. Each woman received a mammogram and breast examination yearly, with biopsies performed based on physicians' clinical judgment.

During the 5.6 years of the study, 199 women in the combined hormone group and 150 women in the placebo group developed breast cancer. Mammograms with abnormal results were more common among women taking hormones than among women taking placebo (35 percent vs. 23 percent); women taking hormones had a 4 percent greater risk of having a mammogram with abnormalities after one year and an 11 percent greater risk after five years.

Breast biopsies also were more common among women taking hormones than among those assigned to placebo (10 percent vs. 6.1 percent). "Although breast cancers were significantly increased and were diagnosed at higher stages in the combined hormone group, biopsies in that group less frequently diagnosed cancer (14.8 percent vs. 19.6 percent)," the authors write.

"After discontinuation of combined hormone therapy, its adverse effect on mammograms modulated but remained significantly different from that of placebo for at least 12 months," they continue.

Use of combined hormones increases breast density, which increases the risk of breast cancer and may also delay diagnosis, the authors note. However, breast density was not measured in the current study.

"Use of conjugated equine estrogens plus medroxyprogesterone acetate for approximately five years resulted in more than one in 10 and one in 25 women having otherwise avoidable mammogram abnormalities and breast biopsies, respectively, and compromised the diagnostic performance of both," the authors conclude. "This adverse effect on breast cancer detection should be incorporated into risk-benefit discussions with women considering even short-term combined hormone therapy."
-end-
(Arch Intern Med. 2008;168[4]:370-377. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: The WHI program is funded by the National Heart, Lung, and Blood Institute, U.S. Department of Health and Human Services. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

The JAMA Network Journals

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.