The Complex Relationship Between Sleep Disorders and Cancer Risk: A Brief Note for Researchers

Sleep disorders, including obstructive sleep apnea (OSA), chronic insomnia, and circadian rhythm disruptions, are increasingly recognized as potentially modifiable risk factors for cancer development. Growing evidence suggests that intermittent hypoxia, chronic systemic inflammation, hormonal imbalance, oxidative stress, and immune dysfunction may serve as key biological pathways linking impaired sleep to carcinogenesis. Epidemiological studies have reported higher risks of breast, prostate, and colorectal cancers among individuals with OSA or shift work-related circadian misalignment, even after accounting for traditional confounders such as obesity and age. In addition, chronic insomnia may contribute to cancer susceptibility through dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, altered melatonin secretion, and weakened antitumor immune responses. This review synthesizes current findings on these associations, identifies important gaps in causal evidence, and emphasizes the need for effective preventive strategies. Targeted interventions, including continuous positive airway pressure (CPAP) therapy, cognitive-behavioral therapy for insomnia (CBT-I), and improved workplace sleep policies, may help reduce cancer risk. Integrating sleep health into public health and cancer prevention frameworks is increasingly important.