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For millions of American women, (HRT) has provided relief from side effects of menopause. As the ovaries stop releasing eggs, a woman鈥檚 body also stops producing the hormones and . This change often affects quality of life due to hot flashes, mood swings, vaginal dryness, and a loss of bone density. HRT replenishes the hormones lost during this process and alleviates the discomfort.
However, many breast and gynecological cancers are driven by changes in hormone levels, leading to widespread fear that HRT increases cancer risk.
鈥淢ost breast cancers are 鈥榝ed鈥 by hormones,鈥 says Cindy Matsen, MD co-leader of the at Huntsman Cancer Institute and associate professor of surgery at the (the U). 鈥淎nytime you鈥檙e manipulating hormones, there鈥檚 going to be effects on breast tissue.鈥
But does HRT directly affect a woman鈥檚 likelihood of getting cancer? Matsen says the answer is complicated.
The Women鈥檚 Health Study
Concerns about HRT and cancer first appeared in the early 2000s. The , a landmark trial that began in 1993, has followed tens of thousands of women to track the development of heart disease, osteoporosis, and breast and colorectal cancer.
Initial results, published in 2003, suggested the use of HRT led to an alarming risk of breast and uterine cancer. These findings attracted a significant amount of media attention, and patients and physicians quickly moved away from the use of HRT. In the Journal of the American Medical Association, researchers estimated that . The next year鈥攔ight after the Women鈥檚 Health Study results were published鈥攑rojected use had fallen to 57 million.
Decades later, Matsen says, scientists are revisiting those early results.
鈥淚 do think that the risk has been a bit overblown. Because of that, a lot of women probably suffered.鈥
Cindy Matsen, MD
鈥淚n more recent years, as the researchers have continued to follow these women and analyze the data more critically over time, it turns out that not every HRT regimen increases cancer risk. It鈥檚 only specific combined regimens of progesterone and estrogen,鈥 says Matsen. 鈥淚 do think that the risk has been a bit overblown. Because of that, a lot of women probably suffered.鈥
Considering the Risks and Benefits
However, taking HRT in the form of progesterone or estrogen alone is not without drawbacks. Artificial progesterone, known as progestin, can increase breast cancer risk. Taking estrogen alone, while protective against breast cancer, may contribute to the development of uterine cancer.
Gender-Affirming Care
Transgender people who are interested in HRT as part of gender-affirming care should also consider these pros and cons, Matsen says, though there are currently no major studies examining the long-term health effects of HRT on the transgender community.
鈥淚n general, anytime you are using any hormone replacement, there is going to be an increased risk of some kind of cancer,鈥 says Matsen. 鈥淏ut I would not deny gender care based on increased risk. It would just be part of the conversation around what the trade-offs are.鈥
鈥淲e are at odds here. From a breast cancer standpoint, we don鈥檛 want women to take progesterone. When it comes to uterine cancer, doctors don鈥檛 want women to take estrogen,鈥 says Matsen. 鈥淪o, it gets very complicated and confusing for people, and it鈥檚 really important to have some careful discussions around personal risk.鈥
Factors to consider are age and family history. Breast cancer, Matsen notes, is also more common than uterine cancer. The American Cancer Society estimates that . Their projection for new 鈥攁 128% difference.
Matsen adds that women going through menopause should consider how much they are suffering.
鈥淚f you鈥檙e going to have terrible side effects from going through menopause, it really may be worth it to go on HRT for a period of time. Usually, doctors will recommend the lowest dose possible for the shortest amount of time possible,鈥 says Matsen. 鈥淚t鈥檚 really a matter of having a careful discussion with your providers about what you're going through and what might help.鈥
Those who decide to use HRT should not feel self-blame if they are diagnosed with breast cancer. Matsen says the breasts are influenced by many hormonal changes throughout a person鈥檚 life.
鈥淚f you get breast cancer, there鈥檚 always going to be thoughts of, 鈥榳hat could I have done to prevent this from happening?鈥欌 says Matsen. 鈥淎nd in the end, we can鈥檛 know for sure. What I generally tell people is to make the best decision you can based on the information you have at the moment. Cancer doesn't happen just because you took HRT. There is no personal responsibility for people who get breast cancer.鈥
鈥淢ake the best decision you can based on the information you have at the moment. Cancer doesn't happen just because you took HRT.鈥