Hi there Francine.
Maybe your Oncologist do not want to remove the tumors because they want it to get smaller, my mom also is stage 4 ovarian cancer and our oncologist won't remove the tumors because it spreaded to some parts of her organ, they want it to get smaller.
I don't really know if your Oncologist reason will be like our Oncologist but if you want to look for a second opinion then I heard this hospital SLOAN-CATERING, I think it's one of the best there in NY.
Take care and I will pray for your mom to get better soon.