Wondering about symptoms of ovarian cancer in the very elderly?

My mother, 90, has been battling lack of appetite, anxiety as well as a generalized anxiety disorder, depression, and multiple gastrointestinal problems for over a year. She is on medication for the anxiety, depression and over time has eaten less and less. Lack of appetite and gas, bloating, etc. She has had a history of IBS, gastritis, and earlier this year was treated for h.pylori. She is just finishing a round of Xifaxin for SIBO, but is not feeling any better. Has an appointment with gastroenterologist in a couple of weeks. Treatment for SIBO is trial and error and I suspect the doctor will next recommend another round of Xifaxin along with another antibiotic. Xifaxin is very expensive and my mother is not convinced she has SIBO. She is also deathly afraid of antibiotics because of previous experiences and because her mother died from C. Diff due to antibiotic use.
I think she probably does have SIBO, I think she has had flare ups in the past and her current flare-up was worsed by the antibiotics she took earlier this year for h.pylori. However, her severe lack of appetite seems out of line with others' experience. I have read ovarian cancer causes lack of appetite and early satiety. She had a CT scan last year that would probably have picked up a tumor of much size? No doctor has mentioned that as a possible problem, and I don't know how to address this without alarming my mother. But she is down to 88 lbs. and wants to live. It's not like she is not eating because she has given up. Although she has to be dragged to the doctor because she doesn't see the need because they don't seem to help her. I know that a doctor once told her that her ovaries dried up and so she has never worried about ovarian cancer. However, she doesn't know that she can still get it. She did have her uterus removed when she was very young. Besides all the pain she has that she is attributing to her IBS, etc., she has had pain in what she describes as around her bladder area.
I though of asking for a CA125 test but getting the test without mother knowing what I suspect would be difficult. If I bring up ovarian cancer, I am afraid her family doctor will want her to go to a gynecologist. Would then have to tell her why, and can't imagine (well, yes I can) her reaction to the idea of going to yet ANOTHER doctor.
She recently had routine blood work and blood sugar checked that seemed normal. Anything else I could ask to be checked? What are main symptoms others have had with ovarian cancer?