Hi everyone, this is my first post in this community and I'm posting to help my mother. We just found out a few months ago that after 15 years of being 'cured', she has a metastasized tumor in her bone with no primary tumor in her breast. She was diagnosed ER-Positive HER-2 Negative 15 years ago (but we are concerned this may have changed). She has one bone tumor now and we're very lucky to have detected it when there was only one. Her CA 15-3 jumped from 25 to 30 (and she also had random fevers), and thankfully our oncologist allowed her to do a PET-CT, from which we found that she had a 1.3cm tumor in her left sacrum with SUV activity of 9.6. She didn't have any pains (again, thankful) and still doesn't.

Her oncologist started her on Ibrance/Femera/Zomeda. In 3 months, she did a PET-CT and her SUV went down to 2.9. This is good and we're very happy. However, what really concerns me is that her CA15-3 did not go down. It's been slowly increasing over the last 5 months (from 30 to 43 over 6 months). I read that sometimes after you start medication, that value might jump up, but it should start becoming meaningful after a month or so, especially its trend over time. I also read that when Ibrance works, people's CA 15-3 numbers do come down. I'm so worried that this means microscopically her tumor is spreading and PET-CT is just not detecting that spread. I feel really helpless because there's not much we can do. The position of her tumor makes it hard for a needle biopsy. My mom really doesn't want to do open surgery. Bone biopsies are complicated since they need to treat the bone. I fear that her tumor type changed and we're not giving her the right treatment. If her SUV value came down, why would the tumor marker not? Also her CA27-29 also shot up from 22.9 (a year ago) to 38.9 (now).

Does anyone else have any experience/know anyone with experience of people taking Ibrance for HER-negative but their tumor marker not coming down but SUV coming down? What does this mean and at least, in your experiences, what has that led to? I rather know what is likely to happen than just hope it doesn't mean anything. Kind of here looking for the truth to best prepare for the future. For example, if this means it's only a matter of time before those marker values translate to tumors, we should perhaps focus the next year on traveling and spending time together while she feels good enough to travel (that is more or less her dream). I was devastated when I first found out about the tumor but now I feel I am strong and want to make the most of my time with my mother. Thank you everyone!