Earlier this week, a new report by the Women’s Health Initiative (WHI) took many by surprise. Mainstream media coverage of the report’s findings suggested that estrogen (without combination with progestin) could reduce breast cancer risk in women who have undergone hysterectomy. The Seattle Post-Intelligencer, for instance, reported, “Estrogen lowers risks of breast cancer, heart attack”. The reality isn’t so simple. As usual, we must look past the headlines to understand what this new information really means – and doesn’t mean.
We agree with the National Women’s Health Network (NWHN): Claims that estrogen will reduce breast cancer risk in women who’ve undergone hysterectomy are misleading.
The WHI study involved postmenopausal women who’d undergone hysterectomy and found no association between estrogen use (for a median of 5.9 years) and risk of coronary heart disease, deep vein thrombosis, stroke, hip fracture, colorectal cancer or total mortality. But although dozens of other studies have shown a link between link between long term use of estrogen and increased risk of breast cancer, this study also indicated a decreased risk of breast cancer that persisted through the time of follow up.
The contradictory findings about breast cancer must be explored and answered before estrogens are touted as a means to reduce breast cancer risk. When we look at the total body of evidence about estrogen use and breast cancer, we agree with the NWHN that it’s premature for women to make decisions about how to reduce risk based on these results alone.
We encourage a deeper look into these findings and we will continue to monitor new reports. As always, we want everyone to know about the science behind the headlines.