SEATTLE — Women not only get some protection from breast cancer while they take estrogen-only hormone replacement, that benefit continues after they stop, according to the latest findings from an expansive national study.
But the findings, released Tuesday in the Journal of the American Medical Association, underscore that when it comes to women’s hormones, nothing is ever simple.
In this case, the double- blind, randomized clinical trial involving nearly 11,000 women with prior hysterectomies has a good — but mixed — message.
For women in the study who used estrogen for several years and then stopped:
• The decreased risk of breast cancer during the years they took hormones continued for years after they stopped.
• The increased risk of stroke during the years they took hormones dissipated.
• But the protection they had from hip fracture while they were taking hormones disappeared gradually.
And — the really mixed part of the message — these findings vary significantly by age.
“These are some of the most favorable findings about estrogen alone we’ve ever published,” said the study’s lead author, Andrea LaCroix, co-principal investigator of the WHI Clinical Coordinating Center, based at Fred Hutchinson Cancer Research Center in Seattle. “It’s certainly a big contrast to the increasingly risky outcomes of estrogen-plus-progestin” treatments.
On average, women were in the study for about seven years and were followed afterward for about four years.
In general, the findings are good for women in their 50s and neutral for those in their 60s, and start to be increasingly negative for women in their 70s, LaCroix said.
For women who were in their 50s when they began hormones, there is a significantly lower rate of death compared with those not using estrogen, LaCroix said.
But “if I were in my 60s or 70s, I would think these findings argue against the long- term use of hormones,” said LaCroix. “For older women, the data clearly argue that there are important risks of being on estrogen alone.”
