Ajax Harwood Clinic
Cancer marker (tumour marker) testing: should I be tested?
Tumour markers to check for 'hidden' cancer
It's normal to worry about a hidden cancer, especially after someone close to you gets sick. Blood tests like CA-125 or CEA are often called tumour markers. They sound like a simple way to check for cancer. In someone with no symptoms, they don't work well for this. They can be normal even when cancer is present. They can also be high for reasons that have nothing to do with cancer. That leads to worry, and sometimes extra tests that were not needed. The good news is Ontario already runs proven cancer-screening programs, for colon, breast, cervix, and lung cancer. These catch cancer early in people with no symptoms. If you have a new lump, bleeding, weight loss you can't explain, or a bad cough, tell your doctor. Those need a direct look, not a blood panel.
Tests you may hear about
Worth asking
Questions you could bring to your doctor:
- Am I due for any of Ontario's organized cancer screening programs?
- Would a tumour marker test like CA-125 help me if I have no symptoms?
- If I'm considering PSA screening, what should I know about the pros and cons?
- What symptoms should prompt more testing right away?
Next steps
Curious what your doctor is weighing up? The clinical page we use for this is open to anyone — it is detailed and written for clinicians, and you are welcome to read it.
Open the clinician reference →Did a naturopath recommend specific tests? Look each one up — what it measures and whether it is usually needed.
Look up a lab test →Want more? Explore the full AHC health library.
Go to ask.ajaxharwoodclinic.com →This is health information and screening — not a diagnosis. Please discuss results with your doctor. In an emergency call 911.