Epidemiology of Pain and Cancer-Related Symptoms

Patients with cancer typically experience multiple symptoms related to cancer and cancer treatment. These symptoms can include physical (e.g., pain, shortness of breath), cognitive (e.g., delirium, memory problems, impaired concentration), and affective (e.g., depression, anxiety) experiences associated with the disease and its treatments (1). Symptoms are the side effects and "toxicities" of treatment, as well as the direct product of the disease process itself. Symptoms are what patients report to clinicians as the subjective negative feelings of physical and mental changes produced by both disease and treatment. Symptom severity is related to the extent of disease and the aggressiveness of therapy. Common symptoms of cancer and cancer treatment significantly impair the daily function and quality of life of patients. Symptoms that are unrecognized by treatment teams may also become so severe that emergency room visits or hospitalization are required for management, adding substantially to the cost of treatment and to the disruption of the patients' routines and those of their families. Untreated symptoms may also negatively influence treatment effectiveness by interrupting treatment (2). Multiple and severe symptoms present a significant challenge to the resources of those who care for and manage cancer patients. For example, intensive cancer therapies produce severe and sometimes life-threatening side effects, resulting in patients' inability to care for themselves and in total dependence on caregivers (3). Undertreatment of symptoms has become a major health problem in its own right.