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The accuracy of tumor markers: a modern scientific view
In modern oncology, laboratory diagnostics plays an extremely important role, and tumor markers have become one of the key tools in the early detection and monitoring of malignant neoplasms. However, the question of their accuracy remains debatable. None of the known markers is completely specific or sensitive, which creates the need to combine these tests with other methods - imaging, histological and molecular genetic.
Scientific determination of tumor marker accuracy
Accuracy in diagnostic tests is understood as an integrative indicator that combines:
Sensitivity — the probability of getting a positive result in a patient with cancer.
Specificity — the probability of obtaining a negative result in a healthy patient.
Predictive value (PPV/NPV) — the extent to which the results can be extrapolated to clinical practice, depending on the prevalence of the disease in the population.
International clinical guidelines (NCCN, ESMO, WHO) state that tumor markers are of limited value for primary screening, but are valuable in monitoring treatment and detecting relapses.
Accuracy of basic tumor markers: clinical data
| Tumor marker | Main localization of tumors | Medium sensitivity | Average specificity | Scientific comments |
|---|---|---|---|---|
| PSA (prostate-specific antigen) | Prostate cancer | 60–80% | 50–70% | Also increases in benign hyperplasia; therefore, used in screening along with digital rectal examination and MRI |
| CA-125 | Ovarian cancer | 70–85% | 50–60% | High values are possible with endometriosis and pelvic inflammatory disease. |
| CEA (carcinoembryonic antigen) | Colorectal cancer, lung cancer | 40–70% | 60–80% | Often elevated in smokers; not recommended for mass screening |
| AFP (alpha-fetoprotein) | Hepatocellular carcinoma | 50–70% | 80–90% | When combined with liver ultrasound, accuracy increases |
| CA 19-9 | Pancreatic cancer | 70–80% | 65–75% | Often elevated in pancreatitis or cholestasis, so diagnostic value is limited |
These data are summarized based on studies published in Journal of Clinical Oncology and recommendations Mayo Clinic.
Factors affecting the accuracy of tumor markers
Biological variations — levels can vary depending on age, gender, and hormonal status.
Comorbidities — inflammatory processes, infections, liver and kidney diseases can increase the indicators.
Pharmacological effects — certain medications can change the levels of tumor markers.
Methodological errors — sample collection, transportation and storage.
Scientific discussions and perspectives
Modern oncology increasingly turning to multigene and molecular genetic tests, which, in combination with tumor markers, can increase diagnostic accuracy. Use biomarker panels, as well as liquid biopsy (analysis of circulating tumor DNA in the blood) may become a more promising method for early cancer detection in the future.
Practical conclusions for clinical practice
Tumor markers should not be used as the sole diagnostic tool.
The greatest value is in monitoring the course of the disease and assessing the effectiveness of therapy.
To increase accuracy, it is recommended to use combined diagnostic strategies (imaging + laboratory + histology).
Patients should understand: an elevated marker level is not a diagnosis, but a reason for further examination.
The accuracy of tumor markers has clear limitations, but when combined with modern diagnostic methods, they remain an important element of evidence-based medicine.
