BackgroundThe European Society of Breast Cancer Specialists (EUSOMA), which aims to standardize the quality of patient care in Europe, has defined quality indicators (QIs) for breast cancer (BC) care to assess compliance to current care standards. These QIs are a useful tool to evaluate care organizations. Only population-based studies are able to assess health system performance in “real-life” situations. This population-based study aimed to describe compliance with several EUSOMA QIs overall and according to patient and organizational factors in France.Methods1 560 adult women with primary invasive non-metastatic BC diagnosed in 2012 were randomly selected among all incident BC from 16 French geographical areas covered by cancer registries. Twelve EUSOMA QIs were selected regarding diagnosis, treatment and staging.ResultsThe minimum standard as proposed by EUSOMA was met for nine QIs related to pre-operative definitive diagnosis, multidisciplinary discussion and treatment (single surgery, breast conserving surgery (BCS) for small BC (<3cm), radiotherapy after BCS or mastectomy for regional BC (pN≥2a), hormonotherapy, adjuvant chemotherapy and trastuzumab). Low compliance was observed for sentinel lymph node biopsy (SLNB) and staging imaging. Adherence to guidelines was usually lower in older patients and in patients with comorbidities. Multidisciplinary discussion was positively related to adherence to guidelines for diagnosis, staging practices (SNLB, imaging) and systemic treatments. Compliance also varied by area of residence and by place of first treatment.ConclusionThis study provides the first current, comprehensive overview of BC quality care at a population level in France. The guidelines were correctly applied in percentage satisfying the EUSOMA standards for the diagnosis and treatment of BC, although staging practices (SLNB, imaging) can be improved. These results highlight the need for continuous measurement of adherence to guidelines to improve BC care.