The off-label use of anticancer drugs is widespread in modern oncology. The potential advantages of such prescriptions are associated with exceeding the expected clinical benefi ts over the risks of complications. The off-label use of anticancer drugs demonstrates the inconsistent efficacy of this approach depending on the type of malignancy, the reasons for prescribing these agents and their belonging to a particular pharmacological group. In a number of situations, the clinical benefits of off-label drugs are more convincing than in case of authorized indications. Currently, prescribing the “old” registered anticancer drugs, used in everyday clinical practice, is seen routine. However, labeling does not reflect the full range of indications with strong evidence of safety and efficacy. The paradigm shift toward molecularly targeted therapy and immunotherapy in various malignancies may increase the off-label use of the specified agents. Lack of treatment options for rare forms of malignancies and exhaustion of the possibilities for registered therapy are the major reasons for off-label prescribing targeted drugs based on the identifi ed molecular genetic disorders. In such cases, the concept of precision therapy is oft en implemented by using agents, the clinical efficacy of which is confi rmed by data with a low level of evidence or with no evidence. Studying the eff ectiveness of the off-label use of anticancer agents is necessary to systematize information and develop algorithms for making decisions about the prescription of these drugs in routine clinical practice.
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