Diving Into the Practical Applications of ctDNA in Oncology Care

In this episode of Oncology Decoded, hosts Manojkumar Bupathi, MD, MS, and Benjamin Garmezy, MD, discussed the role that circulating tumor DNA (ctDNA) may play in the monitoring and management of genitourinary cancers as well as other disease types with their colleague, Arnab Basu, MBBS, MPH, FACP.

The group began by providing an overview of ctDNA’s importance in the field, with Basu highlighting his initial use of the marker when treating patients with colorectal cancer who were experiencing toxicity in the adjuvant setting. Additionally, Basu distinguished between tumor-informed and tumor-uninformed testing, emphasizing an approach that monitors for actionable genes that can inform targeted decision-making from a therapeutic standpoint. Describing how the chance of a false positive is less than 1%, Basu stated that a positive result in the adjuvant setting almost certainly guarantees the need for therapy.

As part of the discussion, the experts considered the utility of ctDNA based on prior findings from studies like the phase 3 NIAGARA trial (NCT03732677), in which higher ctDNA clearance from baseline to the time before radical cystectomy correlated with an enhanced benefit with the addition of durvalumab (Imfinzi) to neoadjuvant chemotherapy. Regarding the potential next steps in the field, the group spoke about the potential use of urine ctDNA testing in bladder cancer, the possibility of investigating the de-escalation of imaging, and the need for additional cross-comparison data on different mechanisms of ctDNA testing.

Bupathi is executive cochair of the Genitourinary Cancer Research Executive Committee at Sarah Cannon Research Institute (SCRI) and medical oncologist with Rocky Mountain Cancer Centers specializing in solid tumors and genitourinary cancers. Garmezy is associate director of genitourinary research and executive cochair of the Genitourinary Cancer Research Executive Committee at SCRI and medical oncologist at SCRI Oncology Partners specializing in genitourinary cancers. Basu is the senior associate consultant and a medical oncologist specializing in the care of genitourinary cancers at Mayo Clinic Comprehensive Cance Center.

Reference

Powles T, Van Der Heijden MS, Wang Y, et al. Circulating tumor DNA (ctDNA) in patients with muscle-invasive bladder cancer (MIBC) who received perioperative durvalumab (D) in NIAGARA. J Clin Oncol. 2025;43(suppl 16):4503. doi:10.1200/JCO.2025.43.16_suppl.4503