CA Level Keep rising - double up every 15 days , PET CT shows nothing

[HelpMedAccount]

Hello All, My mother was diagnosed with Ovarian cancer stage III, last year April. At that time her CA125 was 31,000. She had three rounds of Chemo (Mitotax + Carbo platin). Then surgery in which her Ovary, Uterus, Appendix, and some lymph nodes were removed. Post surgery she had Another 3 rounds of same Chemo therapy. After all this her CA-125 level was 125. Our oncologist suggested two more rounds of Chemo. Her Ca-125 level came to 28. Once her Chemos were stopped, her CA-125 levels are rising ever since. They rosed like - 28-> 50 -> 108 -> 242->350->630. Tests have been done every 15 days. We had gone for PET CT when CA -125 was 242. At that time PET CT was clear. What should we do, Please guide.

[HVAC]

My doctor would have me back on chemo just to keep cancer from growing. The cancer may be spreading but to small to show on a CT. Sorry I do not have better news. Did they also take the omentum with the original surgery? It is the lining of all the major organs. It is called optimum debulking. Did a gyn/oncologist do the surgery? Again I am not a doctor I can only say what they did with me.
Alex