Metformin in breast cancer: antineoplastic contribution or reduction of adverse effects?

Abstract

Background: This study aimed to evaluate the antineoplastic efficacy of metformin in the treatment of breast cancer, as well as to investigate other impacts on the use of this drug during chemotherapy treatment. Methods: This study consisted of a bibliographical review, whose database used to select scientific articles was the “national library of medicine (pubmed)”, whose descriptors were (“Breast Neoplasms/therapy”[Mesh] AND “Metformin”[Mesh]) AND (Chemotherapy OR Chemotherapy-Induced Toxicities) NOT “Diabetes Mellitus, Type 2”[Mesh]. The filters applied to select the works were: last 10 years; written in Portuguese, English or Spanish; excluding systematic reviews and meta-analyses. Results: Recent studies have revealed antineoplastic mechanisms of metformin in the treatment of breast cancer. Despite these mechanisms, there were no relevant statistics that clinically proved this type of therapeutic effectiveness in relation to the drug in question. However, metformin has demonstrated clinical importance as an adjuvant drug, due to its ability to reduce the incidence and severity of adverse effects of chemotherapy drugs, such as peripheral neuropathy, cardiotoxicity, oral mucositis, hepatic steatosis and bone pain. In this way, it can help to facilitate the treatment of patients and preserve their quality of life. Conclusion: The results showed the absence of antineoplastic effects of metformin in the breast cancers evaluated, but relevant control of adverse effects induced by the toxicity of therapeutic protocols. Given this, it is crucial to direct future research to specify which groups of patients with breast cancer are most likely to benefit from the addition of this drug to their anticancer regimen, identifying which drug-induced adverse effects can be reversed or alleviated by biguanide. and thus improve the quality of life of patients.