Difficult pain syndromes: bone pain, visceral pain, and neuropathic pain.

Cancer pain is prevalent in approximately two thirds of all cancer patients and can undermine the quality of life in this patient population. Uncontrolled pain can cause physical as well as psychological distress in cancer patients. As the disease progresses in cancer, pain and suffering increase. Knowledge about pain management is paramount in the comprehensive treatment of cancer patients. Difficult cancer pain syndromes may arise from interruption of bone, viscera, and neural structures by malignant spread of the disease. Familiarity with opioids, adjuvants, and procedures that can abate pain in cancer patients is discussed in a practical manner for clinical application in this text.