‘Don’t mistake tumour markers for cancer screening’: Oncologist explains why

She explains that current international guidelines do not support using these blood tests as a general cancer-screening tool because they have not been shown to reduce cancer-related deaths in the general population.

“Evidence-based cancer screening works best when it is targeted—for example, mammography for breast cancer, cervical cancer screening and colorectal cancer screening in eligible individuals,” she says.

Instead, tumour markers play a different role in medical practice. “They are far more useful in people who already have a diagnosed cancer, where they help monitor treatment response, detect recurrence or assess disease progression,” Dr Pandrowala explains.

What do CEA, CA-125, AFP, CA 19-9 and PSA actually detect?

While these tests are associated with certain cancers, Dr Pandrowala stresses that none of them is cancer-specific.

She explains:

• CEA may be elevated in colorectal cancer.
• CA-125 is associated with ovarian cancer.
• AFP can rise in liver cancer and certain germ cell tumours.
• CA 19-9 is linked to pancreatic and biliary cancers.
• PSA is associated with prostate disease.

“These markers can also be elevated in many non-cancerous conditions such as infections, inflammation, liver disease, pancreatitis, endometriosis and even smoking in the case of CEA,” she says.

Equally important, normal results do not guarantee the absence of cancer. “Many people with early-stage cancers may have completely normal tumour marker levels. A raised result does not necessarily mean cancer, while a normal result does not rule it out,” Dr Pandrowala cautions.

She warns that indiscriminate testing can create unnecessary problems. “False-positive results can lead to anxiety, additional scans and invasive procedures, while false reassurance from a normal result may delay diagnosis,” she explains.

Who should consider tumour marker testing?

According to Dr Pandrowala, these tests should always be ordered based on clinical judgement rather than as part of a routine wellness package.

“Tumour marker testing is appropriate for patients with a known cancer, or when symptoms, examination findings or imaging raise suspicion of a specific malignancy,” she says.

Some high-risk individuals may also benefit from selective testing. “People with chronic liver disease, hereditary cancer syndromes or a strong family history of certain cancers may require specific tumour markers as part of a broader surveillance programme,” she explains.

Even in these cases, tumour markers are never used in isolation. “They are only one piece of the diagnostic puzzle and should always be interpreted alongside clinical evaluation, imaging and other appropriate investigations,” Dr Pandrowala concludes.

The takeaway is simple: while tumour marker tests have an important role in cancer care, they are not a substitute for evidence-based screening or a routine annual test for healthy adults.

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.