Decreasing Treatment for Metastatic HER2-Positive Breast Cancer With Undectable Cancer Levels in Blood Tests.

Heroes is a de-escalation study. Patient must have received continuous anti-HER2 targeted therapy (including Trastuzumab, Trastuzumab/Pertuzumab, Trastuzumab-Deruxtecan, T-DM1) for at least 2 years in any line setting for their HER2-positive metastatic breast cancer with complete response or partial response at last radiological assessment. Patients with ctDNA negative test at baseline will stop their anti-HER2 targeted therapy during the study

"ctDNA test will be performed at 1.5 month after inclusion and every 3 months during 2 years.~Note: For the ctDNA negative patients who become ctDNA positive: ctDNA test will be performed once, 3 months after restarting treatment (+/-1 week)."