Tumor marker analysis

Tumor marker testing is a laboratory diagnostic method aimed at detecting specific substances in blood, urine, or other biological fluids that may indicate the presence of malignant tumors. These substances, known as tumor markers, can be produced either directly by tumor cells or by normal cells of the body in response to tumor growth.

Main tumor markers and their clinical significance

1. CEA (carcinoembryonic antigen): used in the diagnosis and monitoring of colorectal cancer, as well as cancers of the lung, breast, and other organs. Elevated levels may also be observed in inflammatory conditions.
2. AFP (alpha-fetoprotein): a marker of hepatocellular carcinoma and certain ovarian or testicular tumors. Levels may also be increased in chronic hepatitis and liver cirrhosis.
3. CA-125: the principal tumor marker for ovarian cancer. Primarily used for treatment monitoring and early detection of recurrence.
4. CA 15-3 and CA 27-29: used mainly for monitoring breast cancer. Levels may also rise in some benign conditions.
5. PSA (prostate-specific antigen): a marker specific to prostate cancer, widely used for diagnosis, risk stratification, and follow-up.
6. hCG (human chorionic gonadotropin): a marker of trophoblastic tumors and certain ovarian or testicular cancers.
7. SCC (squamous cell carcinoma antigen): used in the diagnosis and monitoring of cervical cancer and squamous cell carcinomas of the head and neck.
8. CYFRA 21-1: applied in the detection and monitoring of non-small cell lung cancer.
9. BRCA1 / BRCA2 (genetic testing): identifies inherited predisposition to breast and ovarian cancer.
10. Thyroglobulin: used for monitoring differentiated thyroid cancer after surgical treatment.

Indications for tumor marker testing

1. Suspicion of malignant disease.
2. Assessment of treatment effectiveness.
3. Detection of recurrence or metastatic disease.
4. Screening in patients with hereditary cancer predisposition.
5. Differential diagnosis between benign and malignant processes.

How the test is performed

1. Preparation. Blood sampling is usually performed after fasting. It is recommended to avoid fatty foods, alcohol, and intense physical activity for 24 hours prior to testing. Before PSA testing, sexual abstinence is advised.
2. Sample collection. Most tumor marker tests are performed using venous blood. In certain cases, urine or biopsy material may be analyzed.
3. Results. Turnaround time depends on the laboratory and usually ranges from 1 to 7 days. Interpretation must be performed by a physician, as tumor marker levels may increase in benign or inflammatory conditions.

Limitations of tumor marker testing

1. Not a standalone diagnostic method. Elevated tumor marker levels do not automatically confirm cancer. Diagnosis requires comprehensive evaluation, including imaging (CT, MRI) and histological confirmation.
2. False-positive results. Marker elevation may occur due to inflammation, infection, or physiological stress.
3. False-negative results. In early stages of cancer, tumor marker levels may remain within normal limits.

Tumor marker testing in Belarus is an important adjunct tool in the diagnosis and monitoring of oncological diseases. However, results must always be interpreted by a qualified physician in conjunction with clinical findings and other diagnostic methods.