Women who have already entered menopause and are taking hormone supplements may be at a higher risk of developing breast cancer, according to a study published in Menopause: The Journal of The North American Menopause Society.
Using breast cancer tumors in an animal model, a team of researchers observed how commonly used estrogens and progestins affected the body. Because their ovaries become inactive, women take these supplements in order to replace the hormones no longer being created.
The results showed that all types of progestin used during the study increased the risk of breast cancer, and the use of estrogen and progestin together or alone would still have the same medical effects. The researchers also concluded that women who have family history of breast cancer should avoid taking progestin supplements.
The team hopes further research will lead to the development of a progestin that wouldnt cause an increased risk of breast cancer, but still protect the uterus.
“Progestins increase the number of blood vessels that are responsible for transporting existing cancer cells,” said Salman Hyder, a biomedical sciences professor at the College of Medicine and the Dalton Cardiovascular Research Center. He added that “the more the blood vessels increase, the higher the chance of cancer cells metastasizing.”
A total of 191,410 women were diagnosed with breast cancer and more than 40,000 patients died from the disease in 2006, the Centers for Disease Control and Prevention reports.