The TREAT ctDNA study & the role of liquid biopsies in breast cancer

In this video Dr Elisa Agostinetto and Prof Dr Michail Ignatiadis, both medical oncologist at the Institut Jules Bordet in Brussels, discuss the rationale and design of the phase III TREAT ctDNA study evaluating the potential of adjuvant elacestrant in patients with hormone-receptor positive (HR+), HER2-negative (HER2-) early breast cancer.

To be eligible for the study, patients need to have stage II or III HR+/HER2- breast cancer, be at an intermediate to high risk of recurrence and be on medium to long duration endocrine therapy (ET). During the first phase of the study, these patients will be screened for a circulating tumour DNA relapse every 6 months. After this screening phase, 220 ctDNA-positive patients without evidence of recurrence on imaging will be randomised in a 1:1 ratio to receive continued ET, or 2 years of elacestrant. Importantly, patients in the study will undergo intensive follow-up with computed tomography and bone scans every 4 months, in addition to the standard annual breast imaging for 3 years. This close follow-up will be done to rapidly pick up oligometastatic disease. The primary endpoint of the trial is distant metastasis free survival, with invasive disease-free survival, relapse-free survival, overall survival, safety and quality of life as secondary objectives.

When asked about the current place of liquid biopsies in the care for breast cancer patients, Prof Ignatiadis must acknowledge that Europe is lagging behind the US. Nevertheless, liquid biopsies and in particular circulating tumour DNA can certainly play a role in the management of breast cancer. For the moment, the most prominent place for this technology lies in the detection of targetable oncogenic mutation in patients with metastatic disease.