I had my first PET scan last week since starting Ibrance and Letrozole in April 2017. There is no evidence of cancer in my body! I was diagnosed in April with breast cancer and bone mets. I think I am still in shock! The meds are working for now, go back in 4 months for another PET scan. I don't think anyone really knows how long these drugs will work because Ibrance is a very new drug. Cancer does give me a different perspective on life. I am living for a cure!!!