Purpose: Comorbid insomnia and cancer-related cognitive impairment (CRCI) are experienced by up to 26% of individuals diagnosed with cancer. This study examined the efficacy and durability of cognitive behavioral therapy for insomnia (CBT-I) on perceived CRCI in cancer survivors.
Methods: Atlantic Canadian cancer survivors with insomnia and CRCI were randomly assigned to receive seven weekly virtual CBT-I sessions (n = 63) or placed in a waitlist control group (n = 69) to receive treatment after the waiting period. Participants completed assessments at baseline, 1 month (mid-treatment), and 2 months (post-treatment). Age- and education-adjusted mixed-effects models using intention-to-treat principles assessed change at post-treatment. Data from both groups were then pooled to assess the durability of effects at 3 and 6 months. A mediation analysis examined whether change in insomnia symptoms mediated the effect of CBT-I on cognitive outcomes.
Results: The mean age of the sample was 60 years, 77% were women, and breast cancer was the most common diagnosis (41%). The treatment group reported an 11.35-point reduction in insomnia severity, compared with a 2.67-point reduction in the waitlist control group (P < .001). The treatment group had a greater overall improvement than the waitlist control on perceived cognitive impairment (P < .001; d = 0.75), cognitive abilities (P < .001; d = 0.92), and impact on quality of life (P < .001; d = 1.01). These improvements were maintained at follow-up. Change in insomnia symptoms fully mediated the effect of CBT-I on subjective cognitive outcomes.
Conclusion: Treating insomnia with CBT-I produces clinically meaningful and durable improvements in CRCI. There is an urgent need increase access to evidence-based treatment for insomnia in cancer centers and the community.
Trial registration: ClinicalTrials.gov NCT04026048.