Cancer risk in patients with sleep apnoea following adherent 5-year CPAP therapy.

Background Increasing evidence suggests that obstructive sleep apnoea (OSA) contributes to cancer risk; however, limited data are available on the impact of continuous positive airway pressure (CPAP) therapy on cancer incidence. We aimed to determine whether adherence to CPAP therapy is associated with a reduction in all-cancer incidence compared to non-adherent patients with OSA. Methods The study relied on the data collected by the multicentre study Pays de la Loire Sleep Cohort, linked to health administrative data, such as to identify new-onset cancer. We included patients who were prescribed CPAP for OSA, with no history of cancer before the diagnostic sleep study or during the first year of CPAP. Patients with documented CPAP use for at least 4 h per night were defined as adherent. Those who discontinued or used CPAP less than 4 h at night constituted the non-adherent group. A propensity-score inverse probability of treatment weighting analysis was performed to assess the effect of CPAP adherence on cancer risk. Results After a median [inter-quartile range] follow-up of 5.4 [3.1–8.0] years, 437 (9.7%) of 4,499 patients developed cancer, 194 (10.7%) in the non-adherent group (n=1817) and 243 (9.1%) in adherent patients (n=2682). The final weighted model showed no significant impact of CPAP adherence on all-cause cancer risk (sub distribution hazard ratio [95% confidence interval]): 0.94 [0.78; 1.14]). Conclusions Adherence to CPAP therapy in OSA patients was not associated with a reduction in all-cancer incidence. Whether adherent CPAP therapy of OSA might reduce the risk of specific cancer sites should be further evaluated.