Pain and the barriers to its relief at the end of life: a lesson for improving end of life health care.

Pain among cancer patients is a common distressing symptom that frequently affects physical functioning, social interaction, psychological status, and quality of life. Despite the extensive body of knowledge available regarding cancer pain assessment and management, it often remains untreated, thereby diminishing the quality of patient care at the end of life. Recommendations on how to remove these barriers, as well as to improve care of the dying in general, need to be implemented by the U.S. government.