Obstructive sleep apnea and cancer: epidemiology, pathophysiology, and clinical aspects

In recent years, the relationship between obstructive sleep apnea (OSA) and cancer has emerged as a new field of investigation. Animal studies on OSA and cancer have been performed more than 10 years ago, while clinical studies are more recent. The current state of knowledge is steadily growing, but several topics still represent areas of uncertainty, including the mechanisms specific for each cancer type, and the epidemiological aspects of the OSA-cancer association. To date, melanoma is the cancer type better characterized from both the biological and the clinical points of view. This updated narrative review summarizes the results of experimental studies on the biology of OSA and cancer, the clinical studies on cancer incidence in OSA patients, and the potential negative effects of OSA in patients with head and neck cancer and lung cancer. The few studies on the effects of positive airway pressure treatment on cancer incidence and aggressiveness or mortality are critically examined, including the potential effects of particles and volatile organic compounds released by PAP devices. Finally, future perspectives are briefly outlined. In conclusion, the relationship between OSA and cancer is complex, and still insufficiently studied. While experimental data indicate biological plausibility of intermittent hypoxia and sleep fragmentation as potential risk factors for cancer in OSA patients, clinical data are too few to draw conclusions, and the question of a possible protective effect of OSA treatment on cancer risk remains unanswered.