Prevalence, clinical characteristics, and risk factors for insomnia in the context of breast cancer.
STUDY OBJECTIVES: To estimate the prevalence of insomnia, describe clinical characteristics of sleep difficulties, assess the influence of cancer on the insomnia course, and identify potential risk factors involved in the development of insomnia among women who had received radiotherapy for non metastatic breast cancer. DESIGN: A sample of 300 consecutive women who had been treated with radiotherapy for non metastatic breast cancer first completed an insomnia screening questionnaire. Participants who reported sleep difficulties were subsequently interviewed over the phone to evaluate further the nature, severity, duration, and course of their insomnia. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Nineteen percent (n=56) of the participants met diagnostic criteria for an insomnia syndrome. In most cases (95%), insomnia was chronic. The onset of insomnia followed the breast cancer diagnosis in 33% of the patients and 58% of the patients reported that cancer either caused or aggravated their sleep difficulties. Factors associated with an increased risk for insomnia were sick leave, unemployment, widowhood, lumpectomy, chemotherapy, and a less severe cancer stage at diagnosis. Among women with insomnia symptoms, the risk to meet diagnostic criteria for an insomnia syndrome was higher in those who were separated and had a university degree. CONCLUSIONS: Insomnia is a prevalent and often chronic problem in breast cancer patients. Although it is not always a direct consequence of cancer, pre-existing sleep difficulties are often aggravated by cancer. It is therefore important to better screen breast cancer patients with insomnia and offer them an appropriate treatment.