It is the aim of the study to reveal the underlying causes of local recurrences and lethality in post-mastectomy patients. A retrospective analysis is done in a series of 293 patients presenting mammary gland carcinoma, operated in the period October 1994 through June 1996. The causes of local recurrences and lethality are linked to the stage of disease (TNM-system), pathohistological patterns of the neoplasm, malignancy degree, as well as inadequate surgical and therapeutic approach against the background of concomitant affections and age factor. The analysis is done using data-base elaborated by the author in computerized program "Paradox 5 for Windows". As shown by the results, in patients with high-degree neoplastic malignancy, inaccurate assessment by the TNM system preoperatively and in 2b and following stages, the rate of local relapses and lethality augment. 1. A more accurate elucidation of the preoperative stage of the disease using instrumental methods is absolutely necessary, since it contributes to reduce the risk of missing single stages in the complex management of this contingent of patients. 2. After obtaining a definitive pathohistological result and malignancy degree assessment, a revision of the complex management protocol worked out in advance is indispensable.