Hello @shireen71 ,
I was diagnosed de novo ER/PR+, HER2 low lobular MBC in January 2022. I started Verzenio + Anastrozole in February. I have mets to bones. My CA markers turned to normal range after I started the meds and stayed liked that. After 18 months, my bone scans showed new sites on bones (mild progression). I wanted to continue for another 3 months and see what would happen. The next scans showed clear progression. All this time my markers were still under the normal limit. Then I was moved to Kisqali and Faslodex. My numbers rose after the first cycle, but then went back down in the second cycle. As a note, I had a liquid biopsy after progression which did not show anything.
My onco follows the CA markers but the main focus is on the scans. Even if the scan shows a progression (bones can be a bit more difficult to read), make sure you combine it with how you feel and other test results. If you feel like there's a conflict, ask for a re-read of the scans.
So, in my case CA markers and the progression was not quite correlated. For some people, the markers clearly go up before a scan shows a clear progression. You will probably see how it works for you.

I hope your line of treatment works great for you with minimal side effects.