Inclusion: 200 patients with colorectal cancer will be investigated before surgery and 100 of them will also be investigated in the same manner after surgery. Due to drop-outs we calculate a need of inviting at least 250 patients.~Exclusion: Dementia, CPAP treated sleep apnea investigations: Patients are investigated with lung function, blood-gas samples, questionnaires, overnight polysomnographic sleep apnea recordings including oro-nasal airflow, thoraco-abdominal respiration belts, chin-EMG, EOG, EEG, ECG (V5) and body position.~Controls: Men and women from two population-based cohort studies the Sleep and health in women and the Men in Uppsala: A Study of Sleep, Apnea and Cardiometabolic Health and older men and women from a local senior organization.~Outcomes: Prevalence of sleep apnea and hypoxia, sleep quality, and lung function, blood gas, STOP-BANG, Epworth sleepiness scale, Mallampati score, symptoms of sleep apnea, surgical complications, mortality, cancer severity.
200 patients with colorectal cancer will be investigated before surgery and 100 of them after surgery.~Investigations will include polysomonographic sleep apnea recordings during one night, lung function measurements, blood gas samples and questionnaires.~Controls: Men and women from two population-based cohort studies