Abstract
Breast cancer is one of the most frequent neoplasms in women in Brazil and in the world. In 2020, it was estimated that 2.3 million new cases were occurring worldwide, while in Brazil, 66.280 new cases are estimated for each year of the triennium 2020-2022, with higher rates in the South and Southeast regions. Melatonin is a neurohormone synthesized by the pineal gland and its secretion r…