Intravenous vs Oral Analgesia in Cancer Patients With Severe Pain After Successful Titration

Pain is one of the most common and fear symptoms for cancer patients, which seriously affects the quality of life in cancer patients. At present, oral opioid is the most common route to administrate cancer pain. However, the patients do not satisfy the pain administration with oral opioid after successful titration in many cases, especially the cases with severe cancer pain. Patient controlled analgesia (PCA) with hydromorphone can take analgesic effect rapidly. The aim of this trial is to compare the maintenance with hydromorphone PCA intravenously or switch to Sustained-Release Morphine orally after successful titraton with hydromorphone PCA intravenously in severe cancer pain.