Insomnia is very common in cancer patients. When left untreated, insomnia can lead to numerous serious consequences (e.g., psychological disorders) for the individual and significant costs for society (e.g., increased medical consultations). Cognitive-behavioural therapy (CBT), a form of psychotherapy, is now considered the treatment of choice for insomnia and its efficacy has been demonstrated in clinical studies conducted in cancer patients. Unfortunately, CBT for insomnia (CBT-I) is not widely accessible as only a few cancer clinics have mental health professionals formally trained in the administration of this treatment. Innovative models of treatment delivery are therefore needed to make sure that every cancer patient with insomnia receives the care he/she needs. A stepped care approach in which patients only receive the level of treatment that they need, beginning with a minimal, less costly, intervention followed by more intensive treatment if required, has shown some promises for other psychological disorders (e.g., depression). Although its relevance has been emphasized to make CBT-I more accessible, its utility has never been investigated. The main goal of this randomized non-inferiority study is to assess the efficacy and costeffectiveness of a stepped care CBT-I as compared with standard care. Our hypothesis is that a stepped care approach will not be statistically inferior in terms of efficacy as compared to usual care, while being much less costly (better cost-effectiveness ratio). Three hundred cancer patients (mixed cancer sites) with insomnia symptoms will be assigned to: (1) stepped care CBT-I (n = 118) or (2) standard care (n = 59), consisting of 6 weekly sessions administered individually by a professional.

Inclusion Criteria:

• have received a diagnosis of non-metastatic cancer (any type) in the past -18 months
• to have an ISI score > 7
• to be aged between 18 and 75 years old
• to be readily able to read and understand French

Exclusion Criteria:

• having a life expectancy < 1 year
• having a severe psychiatric disorder (e.g., psychotic, substance use, severe depressive disorder)
• having severe cognitive impairments (e.g., diagnosis of Parkinson's disease, dementia, or Mini-Mental State Examination score < 24)
• having received a formal diagnosis for another sleep disorder (e.g., obstructive sleep apnea, periodic limb movement disorder)
• shift work in the past 3 months or in the next 12 months
• to have received a CBT for insomnia in the past