CA27-29 nothing on PET

[concernedperson]

Good morning,
I was wondering if anyone had any words of wisdome or experiance.
My mother has Stage iv and has been on chemo for two years now plus herceptin.
She has been considered stable for about 6 months now but her tumor markers have steadily been rising. She got a PET scan but nothing showed up. Nothing shrunk, nothging grew.
So they are keeping her on the same chemo for right now and changing herceptin from every three weeks to every week. Does increasing the time you get herceptin make a difference? Also I know a lot of docs do not go by tumor markers, but if the numbers keep rising doesnt that usually mean something is going on maybe it just cant be seen yet?
Thank you for any advice.

[tricia keegan]

I'm not sure but think chemo itself as well as an infection and certain meds can cause these marker's to rise.
Its a great sign the pet was clear, when I had a mets scare last year my onc was very encouraged by my clear pet scan. Regarding the herceptin I think they just give a lower dosage weekly so it works out the same but I'm sure there are other's here who will know more than I do regarding this but hope your Mom continue's to do as well as she has so far!

[hutchibk]

When my 15.3 TMs (basically similar to CA27/25) went up and my PET/CT showed nothing, we went straight to brain MRI. We found 6 spots which explained the increase. At that point we switched to Tykerb/Xeloda.