Dr. Pusztai on the Promise of ctDNA Assays in Breast Cancer

Lajos Pusztai, MD, DPhil, a professor of medicine and co-leader of Genetics, Genomics, and Epigenetics at Yale Cancer Center, discusses the promise of circulating tumor DNA (ctDNA) assays in breast cancer.

Currently, ctDNA assays are not approved or endorsed for use in breast cancer, says Pusztai. However, testing for ctDNA is gaining ground for monitoring response to immunotherapy in colorectal cancer. 

Notably, during the 2020 San Antonio Breast Cancer Symposium, findings from a biomarker analysis of the I-SPY 2 trial demonstrated that patients with high-risk early-stage breast cancer who did not clear their ctDNA prior to completing chemotherapy had a significantly higher risk of not achieving a pathologic complete response compared with patients who were ctDNA negative.

As such, ctDNA appears to be a highly sensitive tool in the tumor-marker space, Pusztai explains. Although ctDNA is currently a research tool, it has been shown to have higher sensitivity compared with the established, protein-based biomarkers. It is likely that ctDNA assays will demonstrate continued clinical utility and emerge as a useful biomarker in breast cancer, concludes Pusztai.