The purpose of this study is to investigate circadian disturbances after breast cancer surgery by means of monitoring sleep and heart-rate variability, by measuring a metabolite of melatonin in urine and by questionnaires and a sleep-diary.

An increasing number of studies have shown that circadian variation in the excretion of hormones, the sleep-wake cycle, the core body temperature, the tone of the autonomic nervous system and the activity rhythm are important both in health and disease processes. More attention is being paid towards the circadian variation in endogenous rhythms in relation to surgery and whether this can affect postoperative recovery, morbidity and mortality.

Studies have been done on circadian disturbances after major and minor surgery but never in relation to breast cancer surgery.

This study will investigate circadian disturbances in this specific group of patients by using Actigraphy, Polysomnography (PSG), Holter-monitoring (HRV), the primary metabolite of melatonin in urine 6-sulfatoxymelatonin (aMT6s), questionnaires and a sleep-diary.

Inclusion Criteria:

• women, age 30-70, with breast cancer who are admitted for a lumpectomy at Herlev Hospital
• ASA score I-III

Exclusion Criteria:

• Known sleep apnea
• Pre-operative treatment with beta-blockers
• Diabetes Mellitus
• Known pre-operative depressive illness or dementia
• Previous or current cancer
• Known medically treated sleep-disorder (insomnia, restless legs etc)
• Shift-work
• Daily alcohol intake of more than 5 units
• Pre-operative treatment with psychopharmacological drugs, opioids or anxiolytics (including all sleeping pills)
• Predicted bad compliance
• Pregnant or breast-feeding
• Pre- or post-operative complications or events which are expected to increase morbidity or pain the first post-operative days.
• Missing written consent
• Pre-operative MMSE score less than 24
• Urine or fecal incontinence

Department of Breast Surgery at Herlev University Hospital in Copenhagen