It may improve quality of life in certain types of pain. It is unclear if use in chronic pain results in improved quality of life or ongoing pain relief. As of July 1996 study independent of Purdue Pharma, found the controlled-release formulation had a variable duration of action ranging from 10–12 hours. A 2006 review found that controlled-release oxycodone is comparable to instant-release oxycodone, morphine, and hydromorphone in management of moderate to severe cancer pain, with fewer side effects than morphine. The author concluded that the controlled release form is a valid alternative to morphine and a first-line treatment for cancer pain.