During the sexual transition period, transgender people may have to undergo hormone treatment to induce their physical changes. A Dutch study published in the BMJ shows that transgender women (born male) have a higher risk of developing breast cancer compared to the general male population, but a lower risk than the general female population.
The study, supervised by Professor Martin den Heijer from the University of Amsterdam Medical Centre, included 2,260 transgender women and 1,229 transgender men, who had received hormone treatment between 1972 and 2016.
The average age for starting treatment was 31 for transgender women and 23 for transgender men. On average, these transgender people were treated for 13 years in the case of ‘reassignment’ to become women and 8 years to be reassigned as men.
In transgender women, breast cancer was, on average, diagnosed at around the age of 50, after 18 years of hormonal treatment. In transgender men, it appeared at around the age of 47, after 15 years of treatment (less cancer than in the general female population).
The researchers do not comment on the causes, considering that, among other things, they lack information about the hormones used, alcohol consumption, etc. They consider it sufficient for monitoring to be based on what is prescribed for the general female population.