Why did CA125 read "16" but mass was ovarian cancer?

My mom had TAH for mass on right overy a week ago today. Pre-op tests looked positive for a benign tumor. Her CA125 test was only "16". It turnes out that the tumor was malignant for ovarian cancer. How could the reading have been so off? Has anyone heard of something like this? Nancy

Some people just don't react to the CA125. Mine has always been relatively normal, and my onc really doesn't use it as a marker.

Thankfully your Mom's dr. got the mass in time, and did not rely on the CA125 test for diagnosis.

Blessings,
Jeannie

Unfortunately, the CA-125 test is not very reliable, which is why it's not used to screen the general population. A number of women are sensitive to the test, while others have elevated CA-125 and do not have cancer.

I'm sorry your mom is going through this. I was also someone whose tumor was likely to be benign when going into surgery. Getting the news is a shock, I know.

There is a lot of helpful information on this board about ovarian cancer treatment and its side effects. Please continue to post and let us know how your mom is doing and if you or she have questions.

As has been said, CA125 is not a reliable marker for some women. In some it is high due to endometriosis, infection, etc. In others it is normal and they have cancer. I know someone who had a CA125 of 4 and by the time it went to 6 she had a major recurrence. Your mom's doctor will likely follow her with CT or PET/CT scans post surgery to be sure things are shrinking or responding. Fortunately (knock on wood) mine is very reliable.

As others have said, the ca125 number is not always a good marker for everyone.
Thankfully her doctor, hopefully an oncologist/gynecologist, did not just rely on the number but rather looked at the whole picture.
In my case I am very sensitive to that protein marker and my number rises at the slighest occurance. For me that is a good thing.
I am sure that you moms doctors will take very good follow up care of her in every way.
Rosalie

Hi Nancy~

To echo what the other sisters have already said, the CA125 is not a good/reliable marker for everyone.
My sister has ovca and has had a recurrence...her CA125's were always within the normal range.

I wish your Mom the best.

Dear Nancy

You might be interested in this (part of) an article that was sent to me by NOCA (National Ovarian Cancer Association, a Canadian organization), which describes why CA125 is not reliable.

"It is important to emphasize that there is no reliable early detection test for ovarian cancer: in fact screening asymptomatic women using ultrasound, blood tests or pelvic examinations is not recommended by either the Canadian or the US Task force on Preventative Health for the Screening of Ovarian Cancer.

The CA-125 test is an unreliable as a screening tool for the following reasons:
1. It returns a true positive result for ONLY about 50% of Stage I ovarian cancer patients.
2. It has ONLY an 80% chance of returning a true positive result from Stage II, III, IV ovarian cancer patients. The remaining 20% do not show an increase in CA-125 concentrations.
3. A false positive result can be caused by endometriosis, ovarian cysts, first trimester of pregnancy, and pelvic inflammatory disease.
4. The CA-125 test is less likely to detect ovarian cancer in pre-menopausal women, compared to post-menopausal women.

The CA-125 should not be used alone to detect ovarian cancer. However it is useful in conjunction with a transvaginal ultrasound and rectovaginal pelvic exam - only when a woman experiences persistent symptoms."

Hope that helps with the explanation. Take care, and hope things go well for your Mom.

love, Janet J
ovca 1c
taxol, carbo 9 tx.
doxil, gemzar 6 tx.

Hi Nancy,

I, too, am also one of the ones that the CA125 is not a good marker for cancer. I am now going through chemo for a recurrence of my ovarian cancer and my CA has been 'normal'. My doctor no longer uses that as an indicator for me -he lets me get frequent MRI's.

I guess we don't all produce the protein that raises the CA125. Hopefully your mom will be follwed up closely -she should especially be careful to 'listen' to her body -although we tend to get crazy with every little ache and pain once we are diagnosed with cancer ...we usually know when something feels off. That's when you insisit with your doctor to fully check you out. As in my case, I kept telling my oncologist that I felt pain and he kept telling me it was my scar tissues, it couldn't be a recurrence because my CA125 was always normal ...I went to another doctor for a second opinion because I knew this pain was not the same as the one I get with scar tissue. This doctor sent me for MRI's and Cat Scans and sure enough I had several tumors. I returned to my oncologist with the results and he was shocked as well as embarrased. From that day on. he no longer goes by my CA125.

Good luck to your mom.