The purpose of this quantitative and retrospective study was to analyze the prevalence of mammary alterations from 1304 women in the city of Francisco Beltrão-Paraná (PR), Brazil, registered in the SISMAMA system, from a Regional Health Center in Paraná State. Between 2009 and 2012, data was collected in May and June 2013 and statistically analyzed. The results showed that 694 (53.2%) of women were under 49 years old, 1126 (86.3%) had no increased risk for developing breast cancer, and 1205 (92.5%) underwent mammography screening. Color and tracking information were omitted in most entries.The BI-RADS category 0 (inconclusive result) was the most prominent. Categories with higher chances of malignancy (BI-RADS 4 and 5) prevailed in the left breast in women older than 50. Diagnosis of radial sclerosing lesions associated with infiltrating ductal carcinoma was predominant in 53.0% (n = 9) of the histopathological exams. We conclude that these findings are partially supported by the literature.