Due to it's hormonal influence, breast tissue is subjected to many physiological and morphological changes. Breast cancer emerges by rapid growth of malignancy changed cells, and is the most commonly malignant disease in women. Early diagnostics, led by mammography and ultrasound biopsy has a major role to play in improving therapeutic effect, curing the illness and decrease in mortality. By a series of cognition during the history the new kinds of therapy appear and they offer better results and bigger patient's satisfaction. When choosing therapeutic modality, it's important to have a multidisciplinary team of experts. It's role is in individual approach to every patient and whilst choosing therapeutic modality, they consider exact type and stage of disease and also patient's general condition. One of the new therapeutic approaches is preoperative treating of breast cancer, with goal to reduce tumor volume in order to enable breast- conserving surgery. With the combination of breast- conserving surgery and adjuvant radiotherapy results are preserved breast tissue, and same or less mortality rate as radical surgery. Adjuvant radiotherapy by its high-energy ionizing radiation on the target volume can't avoid healthy tissue. That is cause of most unwanted side- effects, especially on skin, and others such as edema, painful an difficult swallowing, pain in the chest or shortness of breath. But with quality planing and care can most of those side- effects be avoided.