Hi Glynnis, I just wanted to add, that I've been on Ribociclib/Letrozole very successfully for some months now (breast/lymph lesions shrunken and bone spots inactive/stable). Despite that the tumour marker has slowly been creeping up. My Onco takes the tumour marker with a bit of a grain of salt, as in itself is not a definite indicator of the cancer on the move, various other factors can also affect how a tumour marker blood test reacts, so in itself is not an definitive indicator :)
Hope it all goes well for you all the same :)
Cheers