Recent Progress in Enhanced Cancer Diagnosis, Prognosis, and Monitoring Using a Combined Analysis of the Number of Circulating Tumor Cells (CTCs) and Other Clinical Parameters

SIMPLE SUMMARY: Counting the number of circulating tumor cells (CTCs) in blood samples has been recognized as being clinically useful. However, challenges like the rarity and heterogeneity of CTCs have limited their widespread use in clinical practice. To address these challenges, a feasible direction is to combine the CTC counts with the routinely used clinical data relevant to cancer detection or screening for analysis. Recent studies demonstrate that this innovative approach has successfully improved cancer detection, prognosis, assessment, and the ability to differentiate between cancers at various stages and with different characteristics. The combination of CTC counts with clinical parameters represents a promising avenue for enhancing the clinical applicability of CTC analysis in cancer management. ABSTRACT: Analysis of circulating tumor cells (CTCs) holds promise to diagnose cancer or monitor its development. Among the methods, counting CTC numbers in blood samples could be the simplest way to implement it. Nevertheless, its clinical utility has not yet been fully accepted. The reasons could be due to the rarity and heterogeneity of CTCs in blood samples that could lead to misleading results from assays only based on single CTC counts. To address this issue, a feasible direction is to combine the CTC counts with other clinical data for analysis. Recent studies have demonstrated the use of this new strategy for early detection and prognosis evaluation of cancers, or even for the distinguishment of cancers with different stages. Overall, this approach could pave a new path to improve the technical problems in the clinical applications of CTC counting techniques. In this review, the information relevant to CTCs, including their characteristics, clinical use of CTC counting, and technologies for CTC enrichment, were first introduced. This was followed by discussing the challenges and new perspectives of CTC counting techniques for clinical applications. Finally, the advantages and the recent progress in combining CTC counts with other clinical parameters for clinical applications have been discussed.