Abstract OT3-4-06: Circulating tumor cells to guide the choice between chemotherapy and hormone therapy as first line treatment for hormone receptors positive metastatic breast cancer patients: the STIC CTC METABREAST trial

Abstract

Abstract Background: Baseline CTC count already demonstrated its accuracy as an independent prognostic marker in metastatic breast cancer (MBC), before the start of any treatment (Cristofanilli, NEJM 2004; Pierga Ann Oncol 2011) for progression free survival and overall survival. Multivariate analyses performed in both a pooled analysis (Liu, ASCO 2011) and in the IC 2006–04 study showed that the other independent prognostic factors were the performance status and hormone-receptor (HR) status. Oppositely, the other criteria that are frequently used to choose between hormone therapy and chemotherapy for the treatment of first line hormone receptor-positive MBC patients (e.g. number of metastatic sites, visceral disease, metastasis-free interval…) were not independent prognostic factors. As CTC count is highly correlated to PFS, we designed a large pivotal phase III trial to evaluate the use of CTC to determine the disease aggressiveness and the choice of first line treatment in potentially hormonosensitive MBC. Trial design: First line metastatic breast cancer patients will be randomized between the clinician choice and CTC count-driven choice. In the CTC arm, patients with ≥5 CTC/7.5ml will receive chemotherapy whereas patients with <5 CTC/7.5ml will receive endocrine therapy as first line treatment. Eligibility criteria: Main inclusion criteria include hormone receptor-positive metastatic breast cancer patients with no previous treatment for the metastatic disease, and who can receive either hormone therapy or chemotherapy as first line treatment. Statistical methods: As every patient will receive a treatment, this pivotal trial has been designed to show a non-inferiority of the CTC arm for PFS (primary clinical endpoint) and a superiority of the CTC arm for the medico-economics study (co-primary endpoint). Present accrual and target accrual: This trial began in March 2012 and more than 15 French cancer centers participate to this study. The accrual of 996 metastatic breast cancer patients should be completed in 2 to 3 years. 20 patients have been included in 2 months in the first opened center. Contact information for people with a specific interest in the trial The STIC CTC METABREAST trial has been funded by the French Ministry of Health (STIC program) and Veridex. The promoter is the Institut Curie (Paris). Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT3-4-06.