Pathology change after chemo

Mmcking3

hi!
i had surgery last week after receiving chemo and herceptin for TPBC diagnosed in July. The pathology from surgery showed a tumor left with different pathology. It was her2 negative the estrogen % was higher and the grade as well as Ki67 were significantly lower. Has this happened to anyone elsw

SmoothOperator78

it's possible that the Herceptin killed most of the Her2/triple-positive cancer cells and that the majority of survivors were just ER+ Positive

Glad to read the proliferation rate and grade were reduced. That's a good sign as it makes things less aggressive for you.

mle42

I didn't have a change in Her2 (started negative, still negative after chemo), but pre-chemo my tumor was ER+/PR+ (both >95%) and high Ki67. After chemo, still ER+ but now PR-, and much lower Ki67. I asked my MO if it was possible to know if the chemo actually changed the characteristics of the residual tumor cells (because of the selective pressure of the chemo, making them change to be slower growing to survive), or if the tumor was really heterogeneous to start with and we killed off one subset of the population and left the rest remaining. She said it wasn't possible to know for sure, but she suspected the former. And if, instead of having surgery to remove the residual tumor, we waited and let it grow for a few months, she would guess that the Ki67 would pop back up to where it was to start with. I think it's probably pretty common for some characteristics to change during chemo - cancer cells are fast dividing, fast to adapt, and it's a survival of the fittest situation when you bombard them with chemo (and herceptin in your case). However, with ER+ remaining high, it means that the endocrine therapy will still work, which is good!

Mmcking3

thank you ladies! The MO said it could’ve been as you suggest mle. The her2 status is what was most interesting, the surgeon and MO both said I could’ve had two different types in the same tumor. And I asked the surgeon because I had to know, if it was possible that the first biopsy findings were incorrect. She said that was also possible. Hopefully the weekly tumor board has some insightful advice