[Epidemiology and diagnosis of breast cancer].

Breast cancer is the most common cancer in women. Family history of breast cancer, age at menarche, number of pregnancies and births, history of breast biopsies, use of hormone replacement therapy and time from the last menstrual period are the key events to note. In addition, a high percentage of cases has been demonstrated in women with a genetically conditioned cancer, i.e. mutations in genes BRCA1, BRCA2, syndromes of Li-Fraumeni, Cowden and Peutz-Jeghers. Over 90% of cases are local or regional when detected. The diagnostics approach consists of self-control, breast palpation by the doctor, breast imaging usually with ultrasound, mammography and magnetic resonance. To confirm the diagnosis, a fine-, core-needle or mammotome biopsy is performed. The final diagnosis is based on a wide panel of immunohistochemical and cytogenetic tests. Histological examination provides accurate assessment of the tumor type, grade, estrogen and progesterone hormone receptor status, HER2 overexpression and Ki67 proliferation index. The data makes possible to qualify to one of four groups of breast cancer biological subtypes, which allows individualized treatment of the patient.