Background: Insomnia affects between 30% to 60% of patients with cancer but to the authors' knowledge little is known regarding factors associated with its development. It has been postulated that adjuvant cancer treatments and their side effects could trigger sleep disturbances in this population but empirical evidence is lacking. The goal of the current study was to assess, separately in patients with breast and prostate cancer, the effect of adjuvant treatments on the evolution of insomnia symptoms and the mediating role of somatic symptoms.
Methods: As part of a population-based epidemiological study, patients with breast cancer (465 patients) and prostate cancer (263 patients) completed at baseline (perioperative period) and 2 months, 6 months, 10 months, 14 months, and 18 months later the Insomnia Severity Index (ISI) and a questionnaire assessing various somatic symptoms.
Results: In patients with breast cancer, radiotherapy (overall effect) and chemotherapy (at 2 months), but not hormone therapy, were associated with increased insomnia severity, whereas androgen deprivation therapy was related to increased insomnia in patients with prostate cancer. In patients with breast cancer, the effect of chemotherapy and radiotherapy on insomnia was found to be significantly mediated by a variety of somatic symptoms, whereas night sweats had a particularly marked mediating role for hormone therapy, both in patients with breast and prostate cancer.
Conclusions: The findings of the current study indicate that cancer treatments and their side effects contribute to the aggravation of insomnia symptoms. Side effects of cancer treatments should be monitored more closely and managed as effectively as possible to prevent the occurrence or aggravation of insomnia.
Keywords: cancer; cancer treatment; insomnia; longitudinal; side effects; sleep.
© 2015 American Cancer Society.