Has anyone experienced an increase in CA 153 levels while on Kisquali and Letroz...

Yes, it has happened to me. That's why my oncologist told me it is only a marker. I've been watching mine for 8 years. It goes up and down between 1-10 points every month. It did not go way up when my cancer progressed. Your scans will be your true guide. Of course, they always cause additional anxiety until I get to read the results.

Thank You so much for your response.

CA 15-3 levels can fluctuate for various reasons, and many patients experience similar ups and downs during treatment. These changes don't always directly reflect treatment effectiveness, as levels can be influenced by factors beyond cancer progression. It would be helpful to discuss these results with your oncology team, as they can interpret the numbers in the context of your overall health picture and other monitoring methods.