Neuropathic pain following breast cancer surgery: proposed classification and research update.

Chronic pain following surgical procedures for breast cancer was once thought to be rare. The results of recent studies, however, suggest that the incidence of chronic pain following breast cancer surgery may be over 50% (Tasmuth et al., 1995; Kwekkeboom, 1996; Fassoulaki et al., 2000). Post-operative sensations reported by patients can be transient or long-lasting, and can include pain, phantom sensations, and sensory loss or changes. Chronic pain can be a source of considerable disability and psychological distress. In patients undergoing diagnostic studies, surgical procedures, and other treatments for breast cancer, persisting pain is an additional burden for individuals already suffering from many psychosocial and medical stressors (Wyatt and Friedman, 1998; Velanovich and Szymanski, 1999; Kuehn et al., 2000). Chemotherapy and radiotherapy can be additional sources of pain and related symptoms and make diagnosis difficult. More patients are surviving breast cancer as a result of progress in diagnosis and treatment. The population at risk for chronic pain and other late complications can therefore be expected to increase in coming years. Although most surgical advances are less invasive and have fewer complications, the rapid pace of change in treatment complicates outcomes research. This article reviews the types of breast cancer surgery and research on the epidemiology and natural history, pathophysiologic mechanisms, treatment, and prevention of chronic pain following these procedures. We emphasize neuropathic pain because it is the most prevalent type, and propose a classification of chronic neuropathic pain following breast cancer surgery that takes into account recent advances in surgical procedures. This classification includes only chronic neuropathic pain syndromes that are a direct consequence of breast cancer surgery. There are other neuropathic pain syndromes that occur following breast cancer surgery that are a consequence of breast cancer and its non-surgical treatment. These syndromes, which include neuropathic pain caused by tumor recurrence and paraneoplastic processes, chemotherapy-associated neuropathy, and radiation plexitis and plexopathy, are beyond the scope of this article. Breast cancer occurs in men with a low incidence (Meguerditchian et al., 2002). Unfortunately, no studies have systematically compared chronic pain in men and women patients following breast cancer surgery; indeed, to our knowledge, only one study of chronic pain following breast cancer surgery has included men (Miaskowski and Dibble, 1995). The nature of the samples studied therefore limits our conclusions to women with breast cancer.