Impact of breast cancer treatments on sleep disturbances - A systematic review.

Sleep disturbances are highly prevalent in women with breast cancer; side effects of cancer treatment may worsen pre-existing sleep problems and have been pointed to as important determinants of their incidence. Therefore, we aimed to assess the association between different types of breast cancer treatment and sleep disturbances, through a systematic review. Medline (using PubMed), CINAHL Plus with full text, PsycINFO and Cochrane Central Register of Controlled Trials (Central) were searched from inception to January 2014. Studies that evaluated samples of women with breast cancer, assessed sleep disturbances with standardized sleep-specific measures, and provided data for different cancer treatments were eligible. A total of 12 studies met the inclusion criteria. Three studies evaluated insomnia, five studies assessed sleep quality, two provide data on general sleep disturbances and two analysed specific sleep parameters. Women submitted to chemotherapy, or radiotherapy, tended to report higher levels of sleep disturbances. More heterogeneous findings were observed regarding the effect of surgical treatment and hormonal therapy. However, a sound assessment of the impact of these treatments was hampered by differences across studies regarding the outcomes assessed, reporting bias and the fact that most studies did not control for the effect of potential confounders. The present review highlights the potential relation between breast cancer treatments and sleep disturbances, particularly of chemotherapy, though more robust evidence is needed for a proper understanding of these associations.