Trends in Prostate Cancer Diagnosis in Transgender Women - Farnoosh Nik-Ahd

June 2, 2023

In this conversation, Alicia Morgans and Farnoosh Nik-Ahd discuss the diagnosis of prostate cancer in transgender women. Dr. Nik-Ahd highlights that despite gender affirmation surgeries, transgender women, who were assigned male at birth, retain their prostates and therefore remain at risk for prostate cancer. Using data collected from the Veterans Health Administration, she discusses the complexities of identifying transgender individuals within electronic records, which often lack precise codes for transgender individuals. The study reveals that transgender women actively on estrogen, a commonly used gender-affirming hormone, showed a higher likelihood of aggressive disease. Despite having lower prostate cancer rates than cisgender men, Dr. Nik-Ahd suggests that physicians should increase their awareness about prostate cancer in transgender women and consider PSA screening due to the potential for more clinically significant cancers. The study marks the beginning of an effort to better understand, diagnose, and treat prostate cancer in the transgender population.


Farnoosh Nik-Ahd, MD, University of California, San Francisco, CA

Alicia Morgans, MD, MPH, Genitourinary Medical Oncologist, Medical Director of Survivorship Program at Dana-Farber Cancer Institute, Boston, Massachusetts

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Alicia Morgans: Hi, I'm so excited to be here with Dr. Farnoosh Nik-Ahd, who is here to talk to us about trans and prostate cancer diagnosis in transgender women. And this is a presentation that she gave at the American Urologic Association annual meeting in 2023. Thank you so much for being here with us today.

Farnoosh Nik-Ahd: Thank you so much for having me. I really appreciate it.

Alicia Morgans: Wonderful. So can you tell us a little bit about the problem, about the issue that we're addressing, and then we'll get into your analysis?

Farnoosh Nik-Ahd: Sure. So transgender women are a rapidly growing segment of our society as there's been progress made in terms of reducing the marginalization and discrimination that has really disproportionately affected transgender people. We expect that the number of individuals who openly identify as transgender will continue to increase. What is important for all clinicians and people to be aware of is that transgender women are people who identify as women, but were assigned male sex at birth. They retain their prostates even after gender affirmation surgeries, so they still remain at risk of prostate cancer. Now, to date, very little has been established about prostate cancer in transgender women. In fact, there's only been 10 case reports on this subject and very few other studies. And so what we wanted to do was really try to understand the scope of the problem and to try to describe the characteristics at diagnosis of prostate cancer in transgender women.

Alicia Morgans: So this is so important in a really unique population. Can you tell me how did you sort of get a cohort together to really investigate this and what did you find?

Farnoosh Nik-Ahd: Yeah, so we chose to study veterans, so people who have their care within the Veterans Health Administration. And we specifically chose this population because the VA is the nation's largest integrated health system. Now, the military has an interesting history with transgender. There's been a lot of progress in recent years going from outright bans of transgender individuals to "don't ask tell" to now transgender individuals being able to enlist in the military and to openly identify as such. So again, we expect this population to continue to increase, including within the VA, but it allowed us a really nice opportunity to perform a national study. So we were able to look at transgender people throughout decades, so ranging from 2000 to 2022 and to get a sense of a nationwide cohort for this population.

Alicia Morgans: Which is so important. And it's interesting that you say that because I imagine that it was hard over time to come out and be transgender in the military population. And as you mentioned, it's sort of an evolving rule system that they had to adhere to. So really, really an interesting cohort of people. And what did you see in terms of prevalence of prostate cancer? What was the sort of incidence of the higher grade prostate cancer versus something that you might follow with active surveillance? It just seems like I have so many questions about this cohort and I'm so glad that you're doing this work.

Farnoosh Nik-Ahd: Yeah, thank you so much. We're really passionate about it as well. So just taking a step back, actually, the really interesting part was when we started doing our work on transgender people, we had a very interesting problem of how do you even identify who is transgender within electronic records? There isn't a single ICD code that's used for transgender individuals. So we started out by actually doing a study just to identify what different codes can be used with high sensitivity and specificity in order to even identify someone as transgender. So to design our study, we stratified all the patients by estrogen use, which was the most common gender-affirming hormone that was being used in this population.

So 116 patients had never used estrogen. 17 had formerly used estrogen but had stopped prior to prostate cancer diagnosis. And 22 were actively using estrogen at the time of diagnosis. Then we wanted to just get a rough estimate of about how many cases per year there were a prostate cancer in this population. So using a previous estimate of 10,000 transgender women in the VA from a previous study we had done, and the median year of diagnosis being 2011, and by diagnosis I mean the transgender identity entry into the medical record, that gave us about 11 years of follow up. And so based off of that, we estimated that there would be 14 cases per year per 10,000 people.

Interestingly, there were trends that transgender women actively on estrogen had more aggressive disease, so they had higher PSA density, and they had the highest proportion of grade group five disease. So to give you numbers, transgender women who were actively on estrogen had about 29% of grade group five disease compared to 12% of those who had never been on estrogen. And just as a point of comparison, previous studies have estimated about 16% grade group four or five disease in cisgender male veterans. So it was a very interesting finding, with the caveat that our numbers are very small. So these are just trends and we would need to do more to really be able to comment on that further.

Alicia Morgans: But so important because I think this population is not necessarily thinking about prostate cancer and then the prostate cancer that then arises might be at higher risk, is really, really important for them as a population, as they're thinking through their day-to-day. And just as we counsel patients who are going through all that they're going through in this situation. So what else did you find, if anything, and how does this affect your practice and how you think about caring for patients who are going through this transgender either transition or living as transgender in the veterans or other populations?

Farnoosh Nik-Ahd: Yeah, I think that there's several key takeaways here. And the most important one is that prostate cancer does occur in transgender women, period. And it does occur, though the rates were ultimately lower than what we had expected based off of comparisons to cisgender men. But it still does occur. And just like you said, their cancers may be more clinically significant just given that we were seeing higher numbers of grade group five disease and higher PSA density. Again, with the caveat that our numbers were small, but definitely something for clinicians to keep in mind.

I think in terms of how this should change practice, it should hopefully increase awareness both among clinicians, whether you're a urologist or somebody else who's providing care for transgender patients, and hopefully also increase awareness for the transgender community that regardless of someone's gender affirmation surgery status, the prostate is still kept in place and therefore transgender women still remain at risk of prostate cancer, so they should at least undergo consideration for PSA screening. From our standpoint, some of the interesting things that we hope to accomplish next are to try to figure out why the rates of prostate cancer were lower in this population. So thinking about how do we establish formal incidence rates in this population? We were only able to roughly estimate the incidence of prostate cancer, but we hope to do that more formally.

And then thinking further about what do PSA screening rates in transgender women look like? What effect does estrogen have on prostate cancer growth and development for those who are transgender? And what barriers exist in terms of PSA screening for transgender women? A lot of patients might not be aware that they have a prostate. They may not, because of stigma or marginalization, there may be some denial of birth sex organs. And so I think this is a first step in thinking through how do we best care for this population and how do we train the next generation and the current generation of physicians and clinicians to better care for this population and to be able to have those conversations with our transgender patients in a thoughtful and inclusive way?

Alicia Morgans: I could not agree more, and I do think that the veterans' population is an opportunity for all of us to really rise to the occasion and within that population, maybe even make more of a difference, raise more of an awareness and have a targeted intervention there that reminds these women that they do still have a prostate. They do still need to be aware of it, and that they may actually, if identified with prostate cancer, have higher risk disease than they would otherwise. So very, very important study here, and thank you so much for your time, for your interest and your expertise. I really appreciated it.

Farnoosh Nik-Ahd: No, thank you so much for having me and for allowing us to share our work with you. We hope to certainly keep going with this work and to try to pave the way for much needed research in this population. So thank you so much for letting us share this with you and stay tuned for more.