Key clinical point: Circulating tumor cell (CTC) count-driven first-line therapy (chemotherapy or endocrine therapy) is noninferior to clinician choice-driven first-line therapy for progression-free survival (PFS) in hormone receptor (HR)-positive/HER2-negative metastatic breast cancer.
Major finding: The median PFS was 15.5 (95% confidence interval [CI], 12.7-17.3) months in the CTC-guided group and 13.9 (95% CI, 12.2-16.3) months in the clinician-driven choice group. The primary end point (PFS in the per-protocol population with a noninferiority margin of 1.25 for the 90% CI of the hazard ratio [HR]) was met with an HR of 0.94 (90% CI, 0.81-1.09). Overall survival was also noninferior with CTC guidance (HR, 0.91; 95% CI, 0.71-1.16).
Study details: In this phase 3 STIC CTC trial, 755 women with HR-positive/HER2-negative metastatic breast cancer were randomly assigned (1:1) to receive a CTC-driven first-line therapy (chemotherapy if 5 CTCs or more/7.5 mL; endocrine therapy if less than 5 CTCs/7.5 mL) or clinician choice-driven first-line therapy (chemotherapy or endocrine therapy) at 17 French centers.
Disclosures: The study was funded by Institut Curie, the French National Cancer Institute as part of the Programme de Soutien aux Techniques Innovantes Coûteuses 2011, and Menarini Silicon Biosystems. The lead author reported receiving grants and nonfinancial support from Menarini Silicon Biosystems during the conduct of the study.
Source: Bidard FC et al. JAMA Oncol. 2020 Nov 5. doi: 10.1001/jamaoncol.2020.5660 .