No, it is not a requirement. However, unlike FTM top surgery where taking hormones does not impact results, taking hormones before MTF top surgery may improve results. Hormone therapy for MTF patients usually results in the development of some breast tissue. This can lead to more natural looking and feeling results. Additionally, it can make the technical aspect of the surgery easier.
This is completely a personal choice, however. Dr. Sessa does not require his transgender patients to take hormones before or after surgery. Some may choose never to take hormones and that is perfectly okay. It should be noted that if you do take hormones, you may need to stop for a few weeks before surgery. This is only temporary and you can resume at a certain point during your recovery.