Breakthrough pain(BTP) is a transient exacerbation of pain with moderate and severe intensity and has high incidence in patients with cancer. Breakthrough pain lacks a consensus international definition and diagnosis standard and is subsequently inadequently clinical treatment , therefore making it more difficult to manage in patients with cancer.The ideal management breakthrough pain may require a combination of pharmacological and nonpharmacological treatment strategies; supplemental analgesia, known as rescue medication, is a common pharmacological treatment option.