Dr Tan on the Use of the Signatera™ Assay in RCC

Alan Tan, MD, discusses the ongoing potential utility of circulating tumor DNA in patients with renal cell carcinoma and highlights how this approach is being used in his own practice.

At the 2023 International Kidney Cancer Symposium, Tan gave a presentation on the use of ctDNA in RCC. Tan states that oncologists currently have access to the Signatera™ ctDNA assay by Natera. Although the likelihood of payer coverage of the cost of these tests is uncertain at the moment, there are numerous ways to leverage this tool across various facets of GUoncology to treat several malignancies, he notes. Tan adds that in cross-specialty discussions, he has observed that the Signatera assay provides substantial information to guide treatment responses. This test serves as an invaluable resource for determining whether patients are responding to treatment or signaling early indications of nonresponse, he emphasizes. Once oncologists receive these assay results, they can stop administering certain treatments to patients in whom they are ineffective. Although treatment decisions should still primarily rely on results from scans, Signatera offers a preview of these results, potentially prompting earlier scans if the Signatera assay indicates a significant shift in patient response, he explains.

Notably, in patients with colorectal cancer, Signatera is already influencing treatment decisions, Tan continues. Although this assay might not be ready for widespread, drastic decision making without validation from a prospective clinical trial, it holds considerable promise, he says. Medicare, for example, is acknowledging its utility, allowing its use in tracking patients undergoing immunotherapy. Signatera is particularly beneficial in this setting because immunotherapy's effects take weeks to months to manifest, Tan says.

Even if the insights gained by monitoring ctDNA kinetics at the start of immunotherapy show an initial uptrend, these findings shouldn't be cause for concern, he expands. The delayed onset of the benefits of immunotherapy aligns with the known dynamics of the immune response, and therefore, oncologists shouldn't prematurely deter the course of immunotherapy based on initial ctDNA monitoring results, Tan concludes.