The term used by the Brazilian Council of Medicine (CFM) is "cirurgia de transgenitalismo" (CFM Resolution No. 1,955/2010).
There are multiple definitions - click on the translation that matches your context.
the surgical procedures necessary to change a person's physical appearance and the functioning of their sexual characteristics to that of the opposite sex
He underwent sex reassignment surgery at the age of 46, following years of preparation for the transformation by having hormone replacement therapy.