Management of dyspnea in advanced cancer patients

Dyspnea is a frequent and devastating symptom among advanced cancer patient s and is often difficult to control. However, there has been considerably l ess emphasis in the literature on the appropriate characterization and mana gement of this symptom than of other cancer-related symptoms. The purpose o f this paper is to review issues relating to the prevalence, causes, progno sis and treatment of dyspnea in patients with advanced cancer. A Medline se arch of the literature published from 1966 to February 1999 was conducted. Dyspnea occurs in 21-78.6% of advanced cancer patients and is reported to b e from moderate to severe in 10-63% of the patients. The frequency and seve rity of dyspnea increase with the progression of the disease and/or when de ath is pproaching. Lung cancer patients with dyspnea have shorter survival than patients with other types of cancer. Dyspnea can be a direct effect of the cancer, an effect of therapy or not related to the cancer or therapy. In addition to cancer, patients may suffer from chronic obstructive pulmona ry disease, congestive heart failure, nonmalignant pleural effusion, pneumo nitis, air flow obstruction, or bronchospasm associated with asthma. In the absence-of lung or heart disease, dyspnea may be a clinical expression of the syndrome of overwhelming cachexia and asthenia or of severe asthenia. M any different causes may co-exist in a patient. Whenever possible, an attem pt should be made to treat underlying cancer. Radiotherapy and chemotherapy may relieve dyspnea also in patients who fail to achieve a major objective response. Symptomatic measures in addition to specific treatments for the underlying cancer and/or other pulmonary and cardiovascular diseases are in dicated. Oxygen therapy has proved effective in hypoxemic and nonhypoxemic patients. The role of transfusion therapy to relieve anemia-related dyspnea in advanced and terminal cancer patients is still controversial. Oral, sub cutaneous and intravenous opioids are effective but underused in these pati ents, whereas currently available evidence does not support the clinical us e of nebulized opioids. While benzodiazepines are frequently used in patien ts with dyspnea, these drugs were ineffective in four out of five randomize d controlled trials. Other components of the symptom expression are better managed by supportive counseling, occupational therapy or physiotherapy. Wh ile the mechanism of breathing and the consequences of different pathologic conditions for both respiratory function and gas exchange are well known, the genesis and pathophysiology of dyspnea as a symptom are much less well understood. Palliative care assessment should be focused on dyspnea as a sy mptom rather than on the functional and gas exchange abnormalities. Increas ed research on the appropriate management of dyspnea is needed.