68P Clinical value of Circulating Tumor Cells (CTC) in the phase III randomized AMBRE trial comparing chemotherapy (CT) vs endocrine therapy (ET) and Abemaciclib in HR+HER2- advanced breast cancer (ABC)

Patients with T1a,b,c N0 breast cancer MP Risk Group 3-Year RFS % (95% CI) pvalue Multivariable HR (95% CI)Conclusions: Among this cohort of pts with clinically early-stage (T1N0 EBC), MP identified pts with H2 tumors (10% overall and 5% among pts with HR+HER2disease) who experienced significantly worse outcomes compared with those with H1 and LR/UL cancers.These findings highlight the prognostic value of MP in clinically small EBC and indicate that a subset of pts with T1N0 may benefit from escalated therapy and biology-informed treatment approaches.Clinical trial identification: NCT03053193.