title: Effect of Melatonin on Cognitive Function and Sleep in relation to Breast Cancer Surgery: A Randomized, Double-Blind, Placebo-Controlled Trial.
abstract: Background. Sleep disturbances and cognitive dysfunction are common in patients with breast cancer. Disturbed sleep leads to poor cognitive performance and exogenous melatonin may improve sleep and attenuate cognitive dysfunction. We hypothesized that melatonin would improve sleep and cognitive function after surgery. Methods. This study reports secondary endpoints from a randomized, double-blind, placebo-controlled trial. Women, 30-75 years, were randomized to 6mg oral melatonin/placebo for 3 months. We assessed postoperative cognitive dysfunction (POCD) with a neuropsychological test battery, sleep with a diary, and sleep quality with VAS. Results. 54 patients were randomized to melatonin (n = 28) or placebo (n = 26); 11 withdrew (10 placebo, 1 melatonin, P = 0.002). The incidence of POCD was 0% (0/20) [95% CI 0.0%; 16.8%] in the placebo group and 0% (0/26) [95% CI 0.0%; 13.2%] in the melatonin group 2 weeks postoperatively (P = 1.00) and 6.3% (1/16) [95% CI 0.0%; 30.2%] in the placebo group and 0% (0/26) [95% CI 0.0%; 13.2%] in the melatonin group 12 weeks postoperatively (P = 0.38). Sleep efficiency was significantly greater in the melatonin group; mean difference was 4.28% [95% CI 0.57; 7.82] (P = 0.02). The total sleep period was significantly longer in the melatonin group; mean difference was 37.0 min [95% CI 3.6; 69.7] (P = 0.03). Conclusion. Melatonin increased sleep efficiency and total sleep time but did not affect cognitive function. The dropout rate was significantly lower in the melatonin group. This trial is registered with Clinicaltrials.gov NCT01355523.
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark ; Department of Breast Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark.
authors.forename: Melissa Voigt
authors.identifier: 0000-0001-7116-2216
authors.initials: MV
authors.lastname: Hansen
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark ; Department of Breast Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark.
authors.forename: Michael Tvilling
authors.initials: MT
authors.lastname: Madsen
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark ; Department of Breast Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark.
authors.forename: Lærke Toftegård
authors.initials: LT
authors.lastname: Andersen
authors.affiliation: Psychiatric Center Copenhagen, Rigshospitalet, University of Copenhagen, 2100 København Ø, Denmark.
authors.forename: Ida
authors.initials: I
authors.lastname: Hageman
authors.affiliation: Department of Anaesthesia, Centre of Head and Orthopaedics, University of Copenhagen, 2100 København Ø, Denmark.
authors.forename: Lars Simon
authors.initials: LS
authors.lastname: Rasmussen
authors.affiliation: Department of Breast Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark.
authors.forename: Susanne
authors.initials: S
authors.lastname: Bokmand
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark.
authors.forename: Jacob
authors.identifier: 0000-0002-0063-1086
authors.initials: J
authors.lastname: Rosenberg
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark.
authors.forename: Ismail
authors.initials: I
authors.lastname: Gögenur