The goal of this observational study is to explore the utility of analytical techniques that enable the study of small amounts of tumor-derived material circulating in the blood, such as fragments of circulating tumor DNA (also known as ctDNA), cells, or other particles. This type of sample is generally referred to as a liquid biopsy, and its analysis is a minimally invasive test, as it only requires the collection of blood samples. The study includes women and men with early-stage breast cancer (EBC) who are about to start neoadjuvant treatment (treatment given before surgery). The main questions it aims to answer are:
* Can liquid biopsy analyses (ctDNA) provide additional information about the type of tumor before treatment starts? * Can these analyses help to detect early whether the tumor is responding to treatment? * Can these tests identify if any cancer remains after neoadjuvant treatment or after surgery? * Is this information related to the risk of the cancer coming back? * Can these analyses, when performed during follow-up, help detect cancer recurrence earlier?
Participants will:
* Continue receiving standard medical care for their breast cancer, including neoadjuvant therapy and surgery. * Provide blood samples at different time points during treatment and follow-up. * Provide residual tumor samples from the routine clinical care.
Written informed consent prior to any specific study procedure.
Patients with willingness and ability to comply with study procedures.
Patients (women and men) ≥18 years of age.
Luminal: Hormonal Receptor(HR)-positive and HER2-negative.
Patients with stage IV BC.
Patients with previous anti-cancer treatment for the current BC.
Patients with diagnosis of any other invasive malignancy in the 5 prior years, unless the malignancy has been treated with curative intent and is considered at low risk of recurrence, with no evidence of active disease at study entry.
Patients with a diagnosis of bilateral or multifocal breast tumors with different HR or HER2 status.