Tumour markers are substances in the blood or other body fluids that may be raised in some cancers. Common examples include CEA, CA-125, CA 19-9, AFP and PSA. They are useful for monitoring treatment response and detecting recurrence in certain cancers, but they are not reliable for diagnosing cancer on their own because they can be raised in non-cancerous conditions and normal in some cancers.
Common Tumour Markers
- CEA: colorectal and some other GI cancers
- CA-125: ovarian cancer
- CA 19-9: pancreatic and bile duct cancers
- AFP: liver cancer and some testicular cancers
- PSA: prostate cancer
- CA 15-3: breast cancer monitoring
- Beta-hCG: some testicular and gestational cancers
- Thyroglobulin: thyroid cancer follow-up
What Can Tumour Markers Do?
- Support a diagnosis when combined with other findings
- Provide a baseline before treatment
- Show how well treatment is working
- Help detect recurrence during follow-up
- Sometimes give prognostic information
What Can They Not Do?
- Confirm cancer without imaging or biopsy
- Rule out cancer when normal
- Replace screening tests for most people
- Always pinpoint the cancer type
Why Can Markers Be Misleading?
False positives
Markers can rise due to:
- Infections or inflammation
- Liver or kidney disease
- Smoking (CEA)
- Menstruation, endometriosis or fibroids (CA-125)
- Bile duct blockage (CA 19-9)
- Prostate enlargement or infection (PSA)
False negatives
Some cancers do not produce markers, so levels may be normal even when cancer is present.
How Are They Used in Follow-Up?
After cancer treatment, doctors may check markers at regular intervals. A steadily rising level may prompt scans to look for recurrence. Trends over time matter more than a single value.
Should Healthy People Get Tumour Marker Tests?
Generally not as a routine screening tool, except in specific situations such as PSA discussions for some men. Random testing can cause unnecessary worry and tests.
Key Takeaways
- Tumour markers support but do not confirm diagnosis.
- They are most useful for monitoring treatment.
- Non-cancer conditions can raise markers.
- Normal markers do not rule out cancer.
- Trends matter more than single values.
Final Thoughts
Tumour markers are helpful tools when used correctly. Interpreting them with your doctor avoids unnecessary worry and supports good decisions. For cancer evaluation and follow-up, you can consult Dr. Varadharajan, a surgical oncologist in Chennai.
