My mom has ovarian cancer. her tumor is shrinking but she still needs chemo. where do i go with this info?

My mom was diagnosed with ovarian cancer in december of this year. Her c125 was way over 6000. It has gone down to below 21 now. Her tumor has shrunk but not enough to stop doing chemo. She had a month off from chemo but the cat scan today showed her tumor had shrunk since the last cat scan. It had shrunk significantly. Where do I go with this information. I am scared and nervous. She is 47 years old.