Background. Despite the fact that sentinel lymph node biopsy (SLNB) in breast cancer patients has become a routine diagnostic procedure, it is still of great interest to researchers, since the priority issues of choosing methodology, equipment, technology, and stages of use are still being discussed. Although all obstacles to this technique implementation into routine clinical practice have been eliminated, SLNB in locally advanced breast cancer is still rarely used. We describe the experience of implementing SLNB in Nizhny Novgorod Regional Clinical Oncology Dispensary. We also discuss organizational, tactical, and practical approaches aimed to minimize the number of errors in technical terms, as well as to choose a multidisciplinary approach to the development of regulations for the examination and treatment of patients with locally advanced breast cancer.Aim. To assess the efficacy of SLNB implementation for patients with locally advanced breast cancer at the regional level.Materials and methods. This study included 500 patients with invasive (T1–2) breast cancer with clinically negative sentinel lymph nodes of all immunohistochemical subtypes that had undergone SLNB and histological examination. Sentinel lymph nodes were visualized using the radioisotope colloid 99mTc-Nanotop. We present the implementation algorithm for this procedure into routine clinical practice and evaluate short-term results.Results. A total of 500 patients have undergone SLNB. The first 30 cases were considered pilot cases, where all patients positive for sentinel lymph nodes additionally underwent standard axillary lymph node dissection. We observed a 100 % concordance of histological results. Then the surgery was routinely performed for all patients from this category. The assessment of short-term surgical outcomes demonstrated significant improvement of the postoperative period, reduced frequency of postoperative complications (persistent seroma of the axillary area to 2.85 %), reduced length of hospital stay (by 52.7 %) and improved functional and aesthetic results in the majority (>62 %) of patients.Conclusion. Our algorithm of SLNB use in patients with breast cancer in routine clinical practice at the regional level allows for rapid method implementation, reduced length of hospital stay, better functional and aesthetic results, and lower incidence of persistent seroma of the axillary area.