Sleep assessment in individuals with cancer

Sleep is defined as a restorative and healthy stage, regulated by endogenous and exogenous factors that coincide over a 24-hour period, being called the circadian cycle or biological clock. Any change in lifestyle can lead to changes in this cycle and, consequently, in sleep.1 The National Cancer Institute José Alencar Gomes da Silva (INCA) describes cancer as a disorderly growth of cells that invade tissues and organs. These cells tend to be very aggressive and uncontrollable, being able to generate tumors and spread to other regions of the body.2 According to INCA, an estimated 625 thousand new cases of cancer in Brazil, in the years 2020/2022. The division of incidence by geographic region shows that the Southeast region concentrates more than 60% of the incidence, with a predominance of prostate and female breast cancers, as well as lung and intestine.2 Cancer is one of the main causes of illness and death in the world, affecting millions of people, partly due to population growth, aging, as well as changes in the distribution and prevalence of cancer risk factors, especially those associated with socioeconomic development.3,4 In patients diagnosed with cancer, the sleep regulatory mechanism is altered, being interrupted for a variety of reasons, such as difficulty in initiating sleep, the presence of nightmares, daytime sleepiness, insomnia, waking up in the middle of the night, staying awake for a long period, difficulty falling asleep and waking up very early.3