Your questions can be very difficult for some of us to answer. As far as the efficacy of the CA 125, it varies from patient to patient. You don't mention your age and that would be important in answering your question. If you are pre-menopausal, the CA 125 can be tricky. The fact that your CT scan hasn't changed, could be considered a mixed blessing. Your cancer has not gotten worse since your last one is looking on the bright side. Of course, your doctor wanted the tumors to shrink if I understand you correctly.
Do you know what Stage your cancer is? And do you know what type OVCA it is?
If you could complete your Profile, it would help us to remember more about you if you post again. And you should post more. This website is very helpful to all of us experiencing this dreadful disease.
I pray that your surgery goes well and they get everything under control.
Teresa
The best you can hope for is that all visible cancer is removed and that you have a low grade cancer. That would be great. A drop in CA-125 is good but it is not always an accurate indicator of amount of cancer.
Certain tumors don't increase the CA-125. The pathology report after surgery will be important to determine what is going on with your cancer and help in selecting additional chemotherapy. There are many options but that you can discuss with your oncologist. They can even give intra abdominal, IP, chemo if minimal cancer and depending on location. God bless and I pray that all cancer is removed during your surgery.