The aim of this study is to describe the use of Instanyl® (Intranasal fentanyl spray) in the treatment of breakthrough pain (BTP) in cancer patients by success of dose titration and distribution of dose strength. Data will be collected at three different time points over a 3 month period.

• Adult cancer patients suffering from BTP
• Instanyl should be prescribed in accordance with the Summary of Product Characteristics (SPC) and none of the stated contradictions applies
• The decision to prescribe should be made independently of the study
• All patients must provide signed Informed Consent prior to inclusion

Adult cancer patients (in- or out-patients) that are suffering from BTP who have not been treated with Instanyl for one month prior to Baseline.