ctDNA Testing Guides Prognosis and Treatment in Oncology

Circulating tumor DNA (ctDNA) testing is becoming an increasingly valuable tool in oncology care, offering insights that extend beyond traditional monitoring methods. In an interview with Oncology Nursing News, Melissa Rikal, FNP-BC, AOCNP, a nurse practitioner at SCRI Oncology Partners, a member of The US Oncology Network, in Nashville, Tennessee, outlined the fundamental ways ctDNA is being applied in clinical practice.

According to Rikal, ctDNA—fragments of tumor DNA shed into the bloodstream by cancer cells—can be used in two primary ways. First, it serves as a prognostic marker. By tracking ctDNA levels over time, clinicians may be able to identify disease recurrence or monitor response to therapy. Rising ctDNA levels can signal possible disease progression, while decreasing levels may suggest treatment effectiveness.

Second, ctDNA can be analyzed through next-generation sequencing (NGS) to identify tumor-specific mutations. Rikal noted that these insights can inform treatment decisions, such as selecting targeted therapies for known mutations or identifying clinical trials that may be appropriate for individual patients.

For oncology nurses and advanced practice providers, understanding ctDNA testing is essential to supporting patient care, communicating results, and helping patients navigate evolving treatment options.

Transcript

ctDNA is essentially fragments of tumor DNA that are shed into the bloodstream by the cancer cells. We’re able to use this in a couple of ways in oncology. One is it can be used as a prognostic indicator in some tumor types and disease types and be able to pick up that tumor DNA in the blood and predict if the cancer is recurring, or to track response to treatment.

If you see an increase in the number of circulating tumor cells, that can be a sign maybe the disease is progressing—or vice versa, if they’re decreasing, that can be a good indicator as well.

The second way we can use it in oncology is by capturing the mutations in that circulating tumor DNA through NGS testing—next generation sequencing—and by looking at those mutations, we are able to help guide their treatment decisions at times. That can be a targeted medicine that is indicated for that tumor type based on a specific mutation that we know to be predominant in that tumor, or we can potentially look for clinical trials based on the mutations that we see in those cells.