Can a blood test detect cancer? Here are the tests oncologist recommends and what they can reveal

From CBC to tumour markers, here are the tests oncologists may recommend and what all these tests reveal.

Early detection plays a significant role in oncology. Diagnostic advancements have established blood-based testing as a valuable component in identifying potential cancer-related physiological changes. Specialised blood tests can detect molecular and biological indicators that prompt further diagnostic workup and timely clinical intervention. In an interview with HT Lifestyle, Dr Ashwani Kumar Sharma, vice chairman - manipal comprehensive cancer centre and onco-robotic surgeries, North-West Cluster, revealed blood tests that can reveal cancer.

Can blood tests detect cancer?

Dr Ashwani said, “Cancer involves the proliferation of abnormal cells that disrupt typical physiological processes or form solid masses.” Certain blood tests assist in detection by measuring altered blood cell counts, elevated protein concentrations, or circulating genetic material.

Cancer involves the proliferation of abnormal cells that disrupt typical physiological processes or form solid masses. (Pexel)

Common blood tests used in cancer evaluation

● Complete blood count (CBC): This test measures the levels of red blood cells, white blood cells, and platelets. According to Dr Ashwani, abnormal counts may indicate blood cancers such as leukemia or suggest that a tumour is affecting bone marrow function.

● Tumour marker tests: These tests measure specific proteins or substances that may be produced in higher amounts by certain cancers. Common examples include Prostate-Specific Antigen (PSA), CA-125, and Carcinoembryonic Antigen (CEA). While helpful, tumour markers alone cannot confirm cancer and are usually interpreted alongside other diagnostic tests.

● Liquid biopsy: A newer and more advanced blood test, liquid biopsy detects circulating tumour DNA (ctDNA), tiny fragments of genetic material released by cancer cells into the bloodstream. It can provide valuable insights into a tumour's genetic profile and assist in treatment planning.

Liquid biopsy can provide valuable insights into a tumour's genetic profile and assist in treatment planning. (Unsplash)

Signs and symptoms to watch out for

While laboratory tests provide supportive data, evaluation of physical symptoms remains essential. Although many of the following signs are caused by benign conditions, persistent symptoms warrant clinical review:

● Persistent fatigue that does not improve despite adequate rest or sleep should not be ignored.

● Unexplained weight loss without changes in diet or physical activity may be a warning sign.

● Frequent fevers, chills, or excessive night sweats can sometimes indicate an underlying health concern.

● Appearance of new lumps, swelling, or persistent pain that does not resolve warrants medical evaluation.

● Ongoing changes in bowel or bladder habits lasting several weeks should be assessed.

● Unusual bruising or unexplained bleeding without an obvious cause may also require further investigation.

“If laboratory analyses, physical findings, or imaging studies suggest potential malignancy, a biopsy is typically performed. This procedure involves collecting a small tissue sample for microscopic evaluation to confirm the presence of cancer cells and establish the specific histological type and stage of disease,” explained Dr Ashwani.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.