Aim. Demonstration the possibility of practical application of the highly sensitive tumor marker CA-62 in the initial diagnosis in asymptomatic patients with suspected cancer and/or the presence of pathological changes in instrumental studies, as well as describe the criteria for interpreting the results to help the doctor make a decision.
 Materials and methods. The article used the results and conclusions of blind clinical trials conducted to detect early stages of breast cancer (BC), prostate cancer (PC), colorectal cancer (CRC) and non-small cell lung cancer using the CA-62 tumor marker and other tumor markers. Statistical analysis was performed using the MedCalc program (MedCalc Software Ltd, Belgium). Diagnostic efficiency was assessed in terms of sensitivity, specificity, test accuracy, PPV and NPV, ROC analysis. The significance level was taken as p0.001.
 Results. The use of the standard cut-off value of 5000 U/ml of the CA-62 tumor marker makes it possible to achieve 97% sensitivity with 95% specificity in stage I BC. The combination of tumor markers CA-62 and CA 15-3 allows achieving 100% specificity in differentiation of BC and benign breast hyperplasia. The use of the CA-62 marker (6500 U/ml) in the gray zone of PSA 2.510 ng/ml improves the accuracy of detecting PC in biopsy from 35 to 93.1% with 90% sensitivity and 97% specificity. The use of a combination of tumor markers (CA-625000 U/ml, CYFRA 21-12.5 ng/ml and CEA5 ng/ml) will allow the doctor to improve the efficiency of differentiating lung cancer from chronic obstructive pulmonary disease. The combined use of markers (CEA3.5 ng/ml) and (CA-625000 U/ml) achieves 100% specificity with 97% sensitivity in detecting early stages of CRC.
 Conclusion. The article shows the possibilities of using the CA-62 marker, as well as new algorithms for the detection and differentiation of early stages of BC, PC, non-small cell lung cancer and CRC and benign neoplasms using the CA-62 marker in primary diagnosis. The use of the CA-62 tumor marker or its combination with other diagnostic methods can be a useful strategy for a comprehensive assessment of the risk of malignant neoplasms and increasing the diagnostic sensitivity of detecting early stages of cancer.