Overview
The goal of this observational study is to assess the prevalence of ESR1 mutations in patients with metastatic hormone receptor-positive/HER2-negative breast cancer in Greece and evaluate the associations of these mutations with disease characteristics, clinical outcomes and real-world treatment patterns.
This study will include participants who have already undergone ESR1 testing as part of their standard medical care. Patient real-world data will be extracted by the patient's medical records. No additional procedures or visits beyond routine care will be required. Data will be collected from routine clinical visits and standard-of-care treatment.
Description
This is a non-interventional, retrospective and prospective observational study conducted in routine clinical practice in Greece with the support of the Hellenic Cooperative Oncology Group. The study involves the collection of primary data from oncology centers, including a representative sample of patients receiving standard-of-care treatment. No changes to current therapeutic practice are required, and all patient management will follow local clinical standards under the discretion of participating physicians.
Eligible participants are patients aged 18 years or older, with histologically confirmed metastatic hormone receptor-positive, HER2-negative breast cancer who undergo ESR1 mutation testing.
The primary endpoint of the study is the epidemiology of ESR1 mutations in the Greek population of patients with metastatic hormone receptor-positive breast cancer, while secondary endpoints include the association of ESR1 mutations with the number and type of prior therapies and correlation with other biomarkers.
Clinical data will be extracted from patients' medical records. Personal identifiers will be pseudonymized, coded, and assigned a unique identification number to protect patient privacy. For the retrospective portion of the study, approval will be obtained from the hospital Scientific Board for patients who are no longer alive, under a waiver of consent.
Patients who consent to participate in optional translational research may provide biological material for further study. This may include paraffin-embedded tumor tissue blocks, surgical specimens, H\&E slides for molecular tumor characterization or digitization for deep learning-based biomarker prediction, and swab samples for germline mutation analysis, provided the patient is alive.
The study will be conducted in accordance with Good Pharmacovigilance Practice, the European General Data Protection Regulation (GDPR), and applicable local regulatory requirements.
Eligibility
Inclusion Criteria:
- Male or female patients, regardless of race, residing in Greece, aged 18 years or older at the start of treatment.
Patients with histologically confirmed metastatic breast cancer with positive hormone receptors and negative HER2 status.
Patients undergoing ESR1 mutation testing.
Exclusion Criteria:
- Patients with metastatic hormone receptor-positive breast cancer who have not undergone ESR1 mutation testing.
