Studying the role of circulating tumor cell clusters in patients with high-risk early breast cancer – GALIA

BACKGROUND: Breast cancer is the most common cancer in women in Slovenia, affecting around 1500 patients per year. Optimal treatment of early breast cancer is crucial, as advanced breast cancer is still an incurable disease. Triple-negative and HER.2-positive subtypes of early breast cancer, as well as inflammatory breast cancer, are among the high­risk subtypes for breast cancer. Liquid biopsy with a non-invasive approach can be used to study different cancer biomarkers: circulating tumour cells (CTCs), circulating tumour DNA (ctDNA) in blood and megakaryocytes. 

PURPOSE: In patients with high-risk breast cancer, we will investigate the prognostic significance of CTC counts, CTC aggregates and megakaryocyte counts for achieving pathological complete response, progression-free survival and overall survival. METHODS: We will enrol 130 patients over 3 years in a prospective, non-interventional study. Inclusion criteria: patients with inflammatory breast cancer regardless of cancer subtype (stage IIID) and patients with non-inflammatory breast cancer with triple-negative and HER.2+ subtype, from stage IIB to IIIA-C, with a medical condition suitable for neoadjuvant systemic therapy. Follow-up of each patient will be 30 months from inclusion. During this time, they will submit blood 6 times for additional tests (CTC and ctDNA). We will also study the impact of treatment on cognitive function and validate the FACT-COG questionnaire for the Slovenian population.

STATISTICAL ANALYSIS: The influence of the studied biomarkers and clinicopathological factors that might influence the achievement of pCR will be examined in a logistic regression model. All biomarkers and clinicopathological factors that could influence progression-free survival and overall survival will be examined in univariate and multivariate Cox analysis. Survival will be demonstrated using the Kaolan-Meier method.