When I started HRT, my doctor responsibly informed me of various health concerns to look out for, including the fact that hormonal medication might change my cancer risk profile. I was receiving an estrogen prescription, and so she pointed out that my risk of prostate cancer might drop, while my likelihood of developing breast cancer might rise. I won’t lie, my brain was stuck on the thought that I could develop breast cancer. That was a moment of gender ewphoria— of having one’s gender identity validated, but in an unappealing way.
Since then, the thought that estrogen could alter my cancer risk has been at the back of my mind. I’ve also found myself wondering whether taking testosterone might similarly alter cancer risk for my transmasc counterparts. To sate my curiosity and get some information about how trans people can manage our collective evolving cancer risks, I spoke with breast surgical oncologist Dr. Monique Gary (DO, MSc, FACS).
Cancer and HRT
Cancers are a group of health conditions that affect different body parts in complex, overlapping ways. They also respond wildly differently to personal factors and treatment. As such, all cancer treatment is personalized medicine tailored to a patient’s exact needs and circumstances.
One factor that influences cancer risk or treatment is our hormonal makeup. Some cancers like those that attack ovaries, prostates, endometria and breasts2 are hormone-dependent, and so trans people will find their risk changing as they medically transition.
How that risk changes is still being studied. Unlike viruses or parasites, cancers are extraordinarily complex conditions that usually can’t be traced to a single source. Most cancers have a complex web of risk factors, and research into them is always difficult, but there’s progress being made.
For one, current data does suggest that trans women on long-term feminizing HRT have a higher breast cancer risk than cis men (it’s still unknown whether our risk of breast cancer matches that of cis women, although current data suggests that our risk is lower). Conversely, we may have drastically lower prostate cancer risk than cis men, as prostate cancer is linked to testosterone activity. Indeed, anti-androgen—or testosterone-blocking—therapy is an effective treatment for some types of prostate cancer because it atrophies and reduces activity in the organ (and many trans women take medication that blocks testosterone).
Data related to trans men and cancer risk is limited. Current treatment guidelines6 and research suggest that cancer risk in trans men on HRT isn’t drastically different from that of cis women—however, this could be due to a shortage of good data. That said, many of the affirming surgeries that trans men undergo can lower the risk of developing some cancers, such as top surgery, which involves the removal of breast tissue and hysterectomies, which involve the removal of the uterus and sometimes the fallopian tubes. Undergoing such surgeries would reduce the risk of developing cancer in those areas.
It’s important to note, though, that gender-affirming versions of these surgeries are not identical to cancer-preventative types. Cancer-preventative surgeries are usually performed by oncologists with a specific focus on removing at-risk tissue, whereas the gender-affirming variants may aim for cosmetic results and retain some at-risk tissues (such as the areolae and nipples). There are cases of trans men being diagnosed with breast cancer after top surgery9, just as there are instances of breast cancer in cis men.
As always, the diversity of surgeries we choose and the varied techniques of surgeons mean that there’s no standard template for gender-affirming surgery. What follows is that there’s no standard way to assess our lifetime risk for complications or illness afterward.
In short: we need more research to reach consensus about trans people’s modified risk of developing certain cancers. However, researchers like Dr. Gary are pushing the data forward everywhere they can
Benefits of HRT outweigh the risks
Dr. Gary emphasizes that cancer prevalence “is more about organs than identity”—a person's anatomy and bodily makeup will always be one of the main determinants of risk. So while there is some evidence to suggest that cancer risk in trans people can change after starting HRT, this doesn’t negate the overall benefits of medical transition.
Broadly speaking, trans people who do not receive gender-affirming care suffer intense risk from other sources that have the potential to drastically shorten our lives, such as a higher risk of stress, suicidality, substance use and self-harm. These much more immediate harms don't compare at all to the slight risk of cancer that HRT might impose.8 “We have to weigh the risk versus the benefit,” Dr. Gary says. “And I think there is a clear-cut benefit to gender-affirming hormone therapies.”
Investigating other factors
While research into HRT and cancer risk is ongoing, recent studies with large samples8, 6 have tended to show no change or only slight changes in trans people’s cancer risk profiles. Those changes in cancer risk are not totally attributable to HRT either—they could also be explained by external factors like smoking and alcohol use, Dr. Gary says.
According to her, trans people can make other lifestyle changes to lower their risk of developing cancers. Old standbys like quitting smoking and alcohol remain probably effective. If able, taking part in light exercise and slowly shifting one’s diet away from highly processed foods and toward vegetables and whole grains—also moves the needle. “Most of those modifiable risk factors are related to depression, smoking, alcohol use, isolation, sun exposure or sedentary lifestyles,” Dr. Gary says.
Self-advocacy is key
Staying involved and up to date on our own healthcare information is also important for prevention. LGBTQ2S+ people often have a fraught and anxious relationship with healthcare due to past harms visited on us by providers and the industry. A relationship with a healthcare provider who is willing to listen is a treasure—one we can cultivate by taking part in our care.
As such, Dr. Gary suggests being an active participant in your healthcare. “Ask the questions,” she says. “Ask for the interpretation, do a little bit of research on your own as well. Stay in it, even if you don’t understand it entirely.”
When it comes to testing, since our care often differs from the norms that medical professionals are trained on, trans people of any gender need to push for treatment that better matches our needs. Like for everyone, knowing our medical and family histories allow us to find screening services that are relevant to us. This could mean performing self-exams and being screened if you have breasts.
For transfeminine people who take hormones, prostate exams are still useful even if emerging research suggests that long-term feminizing HRT reduces prostate cancer risk. There is no medical consensus as to when trans women should start receiving prostate exams. Because there isn’t adequate data for trans people, doctors often default to cis standards, which recommend prostate exams around the age of 50.
If at-risk organs like the uterus, testes or fallopian tubes were surgically removed, doctors or oncologists can still give you an idea of how much tissue was removed and what it means for your long-term prospects.
Ultimately, healthcare is social and societal. External stressors like interpersonal violence, stress and systemic discrimination have far-reaching health effects on marginalized groups. Whenever we can, it’s constructive to strengthen our communal structures, maintain friendships and share our knowledge with others. Those are the powers we have to counteract widespread discrimination and retain agency over our well-being.
