Ca125

What is Ca125?

It is a protein called cancer antigen 125, and is measured through a blood test.

I have high Ca125. Should I be worried?

Although women with ovarian cancer often have high Ca125, having a high Ca125 does not always mean you have ovarian cancer. It is important to know that some women with ovarian cancer never have high Ca125.

There are many normal and non-cancerous conditions that can cause raised Ca125. This include:

• Periods
• Having infection of any sort e.g. pneumonia, urinary tract infections (UTIs)
• Endometriosis
• Pregnancy
• Adenomyosis
• Uterine fibroids 
• Pelvic inflammatory disease (PID)
• Liver, heart, bowel, lung disease

Your doctor will need to take a detailed medical history, perform a physical examination and do a pelvic ultrasound to determine if you need further tests.

Should I include Ca125 in my health screening?

Not if you are at average risk of ovarian cancer. None of the international professional organisations recommend using Ca125 to screen for ovarian cancer in women in the general population at average risk.

This is because many conditions can cause raised Ca125, which means that Ca125 testing is not specific. Even for women at high risk of ovarian cancer (strong family history, genetic mutations etc), there is no consensus on the usefulness of Ca125 test for early detection.

What is Ca125 useful for?

It is useful for monitoring of ovarian cancer treatment, and to monitor for possible cancer recurrence.