The role of obstructive sleep apnea and nocturnal hypoxia as predictors of mortality in cancer patients.

Background: Obstructive sleep apnea (OSA), due to its high prevalence, has been associated with a number of comorbidities, frequently impacting the overall course of these other diseases if left untreated. Recent studies highlight a potential association between OSA and cancer. This study investigates how OSA severity and hypoxia affect cancer prognosis, aiming to elucidate how they interplay.

Methods: Retrospective study including patients with a diagnosis of OSA after any cancer type followed up in a tertiary center during a 10-year period. OSA was mainly diagnosed after level III polysomnographic studies.

Results: Nocturnal hypoxia was significantly more prevalent in patients presenting lung cancer versus other malignancies and was associated with higher rates of oncologic disease progression. Overall survival was significantly lower in severe OSA patients and also in patients presenting nocturnal hypoxia. A composite hypoxia score considering both OSA severity and significant hypoxia was an independent predictor of mortality regardless of clinical cancer staging and treatment. Shorter time between cancer and OSA diagnosis was also associated with worse prognosis.

Conclusion: This study suggests an association between OSA severity and nocturnal hypoxia and increased cancer mortality independently from possible confounding factors such as age, cancer clinical staging at diagnosis, treatment modality and also progression. Neoplastic patients with severe OSA and/or complex hypoxia seem to have lower overall survival rates than those with less severe OSA and nocturnal hypoxia.