Cancer pain: how to measure the fifth vital sign.

Pain assessment is essential to good pain management and quality assurance. A pain-rating scale should be used, in combination with a thorough history and a general physical examination. Radiologic studies are an ancillary component rather than a substitute for this process. Outpatient pain diaries and hospital recordings of pain severity with the vital signs facilitate communication. Part of the goal should be to improve function and quality of life.