Principles & Practice of Pain Medicine > Part V. Pain Syndromes > C. Pain in the Terminally Ill > Chapter 44. Cancer Pain Syndromes Stuart W. Hough and Ronald M. Kanner

Cancer Pain Syndromes

"Most pain syndromes in patients with advanced cancer are caused by direct tumor invasion of pain-sensitive structures. The specific pain syndrome depends more on the type of structure involved (e.g., bone pain, visceral pain, mucosal irritation) than on the causative tumor. Similarly, though less commonly, the injury is iatrogenic from diagnostic, surgical, chemotherapeutic, and radiotherapeutic interventions. In many patients, pain has multiple causes. Since increasing pain may signal advancing disease, determining its cause is important.¹⁶ In addition, knowing the cause of pain assists in selecting the most appropriate analgesic approach. The following are several common, recognizable painful conditions that occur in cancer patients. They are grouped according to the type or location of pain.Tumor involvement of bone is the most common cause of cancer pain.⁷ Any tumor may involve bone, but the most common include metastatic cancer of the breast, lung, prostate, and thyroid, and multiple myeloma.¹ This is purely somatic pain, unless pathologic fracture or tumor extension disrupts nerve. As such, pain is usually described as focal and constant, but may be referred. Typically, patients experience several days or weeks of increasing pain. Acutely increased bone pain may signal fracture or neural impingement. Tumors may activate nociceptors by pressure, ischemia, or secretion of algesic substances (e.g., prostaglandin E2, osteoclast activating factor).¹⁷ Most pain is probably sensed in periosteum..."