Safety and Effectiveness of Transdermal Buprenorphine in Cancer Pain

Inclusion Criteria: 1. Cancer patients aged 20 years old and over 2. ECOG \<3 3. Moderate or severe pain intensity with stable titration from previous opioid analgesics, 7 days at least prior to enrolment and with the dose equivalent to oral morphine ranging from 60 to 120 mg/day in previous treatment 4. Cancer-related pain that requires treatment with continuous around-the-clock strong opioid analgesic 5. Patients who are going to start Transtec treatment per clinical judgment, according to the locally approved labeling, are eligible. 6. Patients who are able to communicate and fill out the questionnaire forms 7. Patient provided signed informed consent Exclusion Criteria: 1. Patients diagnosed with non-cancer pain or unexplained pain 2. Patients who have constipation (CTCAE grade 3 and above) 3. Patients with uncontrolled or unstable cardiac disease 4. Abnormal lab results, with obvious clinical significance, such as ALT or AST\>= 3 fold of upper limit of normal value or liver function of Child C grade prior to study 5. ALT or AST \>= 5 fold of upper limit of normal value for patients with liver metastasis or primary liver cancer 6. Pregnant or nursing (lactating) women 7. Patients who are drug or alcohol abuse 8. Patients who have hypersensitivity to buprenorphine 9. Patients who are clinically unstable or have a life expectancy of less than 8 weeks making completion of the trial unlikely 10. With any contraindications or using prohibited medication per locally approved