Prior to 2002, hormone replacement therapy (HRT) was routinely given by doctors to millions of women across America who was going about their daily lives feeling out of sorts.
One woman, Paula, recalls when she began taking a combination of estrogen and progestin, a man-made version of progesterone, to ease her natural menopausal symptoms. “I just felt flat, irritable, and like I just couldn’t get enthused about doing anything. Honestly, I felt like I hadn’t had a good night sleep for years and the life force was just being sucked right out of me.”
When Paula started HRT, besides quelling her hot flashes and easing vaginal symptoms, it was thought to have positive long-term benefits such as preventing heart disease and osteoporosis, and lowering the risk for colorectal cancer. For millions of women like Paula, it seemed like a Godsend. But attitudes changed abruptly when the landmark Women’s Health Initiative study found that the treatment actually posed more health risks that benefits for postmenopausal women.
As more and more studies began linking HRT to an increase in breast cancer, ovarian cancer, and lung cancer, among other health hazards, doctors became less likely to prescribe it and most women already taking HRT discontinued use, often without telling their physicians.
Now a new analysis of the California Teachers Study which looked at HRT use among 2,857 women for almost a decade confirms what an 2009 analysis by Harvard Medical School professor Joann Manson found: in the initial two years of HRT there was no increase in the number of breast cancer cases in patients receiving combination hormone therapy. However, over five to six years of HRT, those odds significantly increase.
“This is evidence that the story is complicated," said Tanmai Saxena, an M.D. and Ph.D. student at the University of Southern California Keck School of Medicine, who authored the new study report published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.