To present an overview of the epidemiology and pathophysiology of cancer pain related to disease and treatment.Published manuscripts, Web sites, and textbook chapters.Current knowledge of cancer pain epidemiology and pathophysiology widens and focuses the opportunities to prevent, limit, and treat cancer pain.Nurses' knowledge of transduction, transmission, perception, and modulation in cancer pain pathophysiology outlines pathways for multimodal approaches to treat complex and diverse pain experiences. Use of standard vocabulary of pain terms and definitions facilitates pain assessment and management across different disciplines.