Dr Pusztai talks to ecancer about the DARE trial (NCT04567420) which investigated the use of circulating tumour DNA (ctDNA) to monitor early relapse in high-risk ER+/HER2- breast cancer patients undergoing adjuvant endocrine therapy.

Of 494 patients tested, most were ctDNA-negative, showing a 99% recurrence-free survival rate after 12 months, indicating high negative predictive value. Forty ctDNA-positive patients were randomized to either standard treatment (Arm B) or intensified therapy with fulvestrant + palbociclib (Arm A). Arm A showed a higher ctDNA clearance rate (63% vs. 22%).

Rising ctDNA levels post-randomization predicted recurrence, while decreasing ctDNA was associated with better outcomes.

The findings support ctDNA as a reliable tool for early relapse detection and risk stratification in this cancer.