Impact of melatonin use on the oxidative profile of breast Cancer patients undergoing palliative chemotherapy: clinical trial

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 rate is directly related to the circadian cycle, which synthesis happens in the absence of ambient light, peaking between 2 and 4 o'clock in the morning. Recent studies show an important relationship between breast cancer and melatonin. Thus, it is possible to verify a decrease in plasma melatonin levels in cancer patients when compared to their healthy congeners, thus, some studies suggest the use of melatonin by these patients. The effect of melatonin as an antioxidant agent in the fight against free radicals and its anticarcinogenic potential has been demonstrated, with the induction of apoptosis, controlling the spread of tumors. Thus, some studies suggest the use of melatonin as an adjunct therapy to chemotherapy for its antioxidant potential in healthy cells, pro-oxidant and pro-apoptotic in tumor cells, and immunomodulator; which possibly improves the quality of life of patients. Thus, the objective of this work is to verify the pro-oxidant potential of melatonin in tumor cells in patients with breast cancer, since patients will perform the use of melatonin for 28 days (in 2 separate stages), which may slow oxidative stress in the body of these patients. (AU)