Evaluating the Potential for Circulating Tumor Cells as a Diagnostic and Prognostic Biomarker in Various Cancer Types

Abstract

Circulating tumor cells (CTCs) are cells that can be found circulating in the peripheral blood of cancer patients. They originate from primary solid tumors and are thought to contribute to metastases and poor prognosis. Since cancer treatment is shifting toward greater personalization, a major goal in the field is the development of less invasive and more cost-effective measures in diagnosis, staging, treatment, prognostic implications, and surveillance of cancer. Utilizing CTCs as a biomarker from a “liquid biopsy” or sample of patients’ blood would be transformative in accomplishing this goal. In this review, we aim to critically assess current pre-clinical and clinical literature over the past two decades implicating CTCs’ potential for use as a predictive biomarker in various cancer types either in addition to or instead of current standards of care. We also are interested in understanding several aspects of CTCs including the role CTCs play in resistance to treatment, the immune system evasion properties of CTCs, the feasibility of using CTCs in clinical practice, and the utility of CTCs for predicting outcomes including patient survival. Furthermore, here we discuss gaps in the literature, limitations of CTCs, potential for their other uses, as well as the significance of CTC detection in patients following surgery.