This recent paper in the British Medical Journal on breast cancer risk in transgender people receiving hormone treatment sparked my interest because not only did it draw attention to a group of people all too often overlooked by cancer researchers but it showed us why expanding our focus can provide us with new insights into breast cancer.
The study, conducted by a research group in Amsterdam, compared the incidence and characteristics of breast cancer in 3,489 transgender people in the Netherlands to that seen in the general Dutch population. The transgender group included 2,260 adult transwomen (people assigned male at birth who now identify as female) and 1,229 adult transmen (people assigned female at birth who now identify as male).
Eighteen of the 2,260 transwomen and four of the 1,229 transmen reporting having been diagnosed with breast cancer, a rate significantly higher than breast cancer diagnoses expected to be found in a group of cisgender males (men assigned male at birth) but significantly lower than what would be found in a group of cisgender women (females assigned female at birth). The researchers say this suggests that transgender people alter the breast cancer risk they were born with after they start taking hormone therapy.
This is fascinating on several fronts. First of all, it once again confirms the connection between hormones and breast cancer. In general, in cisgender men breast cancer is not common; some are at higher risk because they were born with an inherited BRCA mutation. Theoretically, cisgender men should have short ducts behind their nipples, the type we’d expect to see in a prepubescent girl. But in actual fact, we don’t know. We do not have an anatomical map of the human breasts of women or men.
Much more research is needed on breast cancer risk in transgender and cisgender women and men. All people across all gender identities should learn as much as they can about their breast cancer risk and talk to their doctor about if or when to start breast cancer screening, especially if they have a strong family history of the disease.
It also makes me think that the Foundation may want to use our new handheld ultrasound to look at breast ducts in cisgender men, transmen and transwomen to get a sense of how they differ from the breast ducts of cisgender women. This is why we want everyone—cisgender, transgender, gender questioning—to be part of Love’s Army! Haven’t yet signed up? Sign up now! And tell everyone you know to sign up, too!