Insomnia and other sleep disturbances are very common in individuals diagnosed with cancer, and it is often helpful for patients to hear this. A good history of other contributors to sleep disturbance can be helpful as well. Often, depression, anxiety, and pain, as well as other stimulant medication...

There is good evidence that CBT-I (Cognitive Behavioral Therapy for Insomnia) can be effective. It has been shown to work directly and remotely. Other options include acupuncture. In a randomized trial comparing acupuncture to CBT-I, both resulted in improvement, although the effects from CBT-I were...

Ensure it isn't a recent change related to medications. Steroids are notorious for disrupting sleep patterns, among other side effects, and tapering off the steroids as quickly possible will usually fix the problem.

Here is a good Q&A on managing insomnia from the perspective of sleep medicine.