Hormone therapy may up risk of aggressive breast cancers

Women who undergo hormone-replacement therapy (HRT) to treat symptoms of menopause are at an increased risk of developing aggressive breast cancers, a new study has warned.
US researchers found postmenopausal women on hormone replacement therapy that included both estrogen and progestin were 1.5 times more likely to develop breast cancer over an 11-year period compared with women not on the hormones.
HRT increased the risk of breast cancers that have a low risk of recurrence, such as estrogen-receptor-positive cancers, as well as the risk of more aggressive breast cancers, such as triple-negative breast cancer, the study found, MyHealthNewsDaily reported.
The findings support the results of a study published last year that suggested HRT increased the risk of all categories of breast cancer. Before that study, doctors thought that HRT only increased the risk of less-serious cancers, said study researcher Dr Rowan Chlebowski, of the Los Angeles Biomedical Research Institute.

The decision to start HRT should be made on a case-by-case basis, Chlebowski said. Women should speak with their doctors about the risks and benefits of the therapy. The benefits will be greater for those with more severe symptoms of menopause, Chlebowski said.
The new study analysed information from 41,000 postmenopausal women ages 50 to 79, about half of whom were taking HRT (estrogen plus progestin) at some point in the study, and half who were not on the therapy.

During the study period, about 2,200 women were diagnosed with invasive breast cancer. Among those who took HRT, 0.6 per cent developed breast cancer each year, compared with 0.42 per cent for those who weren't on HRT.

Women's survival after a breast-cancer diagnosis was about the same for both groups. However, because more women who took HRT developed breast cancer, the findings suggested that the use of HRT may increase deaths from breast cancer in the population as a whole, the researchers said.
The study was published in the Journal of the National Cancer Institute.