The Use of Circulating Tumor DNA to Monitor and Predict Response to Treatment in Colorectal Cancer

Mifanwy Reece; Hariti Saluja; Paul Hollington; Christos S Karapetis; Sina Vatandoust; Graeme P Young; Erin L Symonds

doi:10.3389/fgene.2019.01118

The Use of Circulating Tumor DNA to Monitor and Predict Response to Treatment in Colorectal Cancer

Front Genet. 2019 Nov 21:10:1118. doi: 10.3389/fgene.2019.01118. eCollection 2019.

Authors

Mifanwy Reece¹, Hariti Saluja^{2

3}, Paul Hollington¹, Christos S Karapetis^{3

4}, Sina Vatandoust⁴, Graeme P Young³, Erin L Symonds^{3

5}

Affiliations

¹ Colorectal Surgery, Division of Surgery & Perioperative Medicine, Flinders Medical Centre, Bedford Park, SA, Australia.
² Department of Medicine, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia.
³ Flinders Centre for Innovation in Cancer, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia.
⁴ Department of Medical Oncology, Flinders Medical Centre, Bedford Park, SA, Australia.
⁵ Bowel Health Service, Flinders Medical Centre, Bedford Park, SA, Australia.

Abstract

Background: Colorectal cancer is one of the most common cancers worldwide and has a high mortality rate following disease recurrence. Treatment efficacy is maximized by providing tailored cancer treatment, ideally involving surgical resection and personalized neoadjuvant and adjuvant therapies, including chemotherapy, radiotherapy and increasingly, targeted therapy. Early detection of recurrence or disease progression results in more treatable disease and is essential to improving survival outcomes. Recent advances in the understanding of tumor genetics have resulted in the discovery of circulating tumor DNA (ctDNA). A growing body of evidence supports the use of these sensitive biomarkers in detecting residual disease and diagnosing recurrence as well as enabling targeted and tumor-specific adjuvant therapies. Methods: A literature search in Pubmed was performed to identify all original articles preceding April 2019 that utilize ctDNA for the purpose of monitoring response to colorectal cancer treatment. Results: Ninety-two clinical studies were included. These studies demonstrate that ctDNA is a reliable measure of tumor burden. Studies show the utility of ctDNA in assessing the adequacy of surgical tumor clearance and changes in ctDNA levels reflect response to systemic treatments. ctDNA can be used in the selection of targeted treatments. The reappearance or increase in ctDNA, as well as the emergence of new mutations, correlates with disease recurrence, progression, and resistance to therapy, with ctDNA measurement allowing more sensitive monitoring than currently used clinical tools. Conclusions: ctDNA shows enormous promise as a sensitive biomarker for monitoring response to many treatment modalities and for targeting therapy. Thus, it is emerging as a new way for guiding treatment decisions-initiating, altering, and ceasing treatments, or prompting investigation into the potential for residual disease. However, many potentially useful ctDNA markers are available and more work is needed to determine which are best suited for specific purposes and for improving specific outcomes.

Keywords: chemotherapy; circulating tumor DNA (ctDNA); colorectal cancer (CRC); methylation; mutation; surgery.

Publication types

Review