Her 2 climb with doxil (doxorubicin)

[Nguyen]

I now remember something that bother me a bit, in your 2014 biopsy you wrote now ER+ 90% staining, I assumed it’s still Her2 positive, based on continuing treatment with trastuzumab based therapy. Trastuzumab based therapy could negatively impact the heart, with LVEF of 4X percent, it is puzzling to consider adding doxil to any regiment with trastuzumab component. Doxil is in the anthracycline family and could impact the heart negatively in addition to trastuzumab based medicine. I hope your oncologist would closely monitor your heart perhaps monitoring GLS in addition to LVEF. GLS is a leading indicator of LVEF. If the oncologist is not familiar with GLS, perhaps consult a cardiologist for further opinion.

Lastly, one mechanism of resistance to regimens that target her2, is the tumor could change (or being more positive) to ER+ and/or PR+ from negative. I don’t see a component in the later regimens to block the ER/PR pathway. Since you had been treated with aromatase inhibitor before, your tumor likely develops ESR1 mutation. This can be checked with gene sequence, although I think there is a cheaper test. Aromatase Inhibitors do not work well (if at all) for tumor with ESR1 mutation. Fulvestrant/Faslodex will work to some degree. Perhaps you can also discuss all this with your oncologist.

Good luck.