It may be feeding of estrogen
and this would mean that you would have to get off the
premarin and likely even take an estrogen antagonist, which will help keep the estrogen away from the cancer. or your doctor may just decide to go off the premarin.
depening on thbe kind of the cancer, and it's severity, you may, or may not be referred to a medical oncologist, and even a radiation oncolgist, at which time chemotherapy and surgery would be addressed.