I was on letrozole - 10 years, finished over a year ago. I keep up yearly checks with my oncologist and biennially with my surgeon. But as @arpie says, anything at all out of whack, I get it checked. Just as there seems to be no such thing as someone 'who would never get cancer', there is absolutely no guarantee you can't get it twice. But forewarned is forearmed. No medical professional worth their salt will consider getting something checked silly or panicky. My experience has been that such checks have been rare (and nothing bad discovered!) but they are worth the time and cost for peace of mind and an early fix if required - my surgeon is a whiz at lumps and recommended (and did) a mole removal I hadn't thought about. It wasn't cancerous but he felt it might go that way. We learn a lot while going through cancer treatment - worth keeping that learning in mind afterwards. Best wishes.