HE INDIVIDUAL with cancer is at risk of experiencing difficulty in breathing or changes in respiratory function related directly to the disease itself, secondary effects of the disease, or problems related to immediate or long-term effects of therapy. Three major functions are necessary for normal respiratory function: normal and unobstructed anatomical respiratory structure; normal tissue elasticity and expansibility of lung, rib muscles, and diaphragm; and normal vascular supply of adequate gaseous components in blood to both sides of the blood-gas barrier. PREEXISTING ALTERATIONS IN OXYGENATION AND/OR VENTILATION Preexisting respiratory conditions resulting in alterations in oxygenation and/or ventilation, ie, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), and anemia, impact on clinical status, proposed therapies, prognosis, and nursing management of the patient with cancer. 2-~2 Other commonly occurring conditions affecting respiratory function are chronic bronchitis, pulmonary emphysema, and a variety of pulmonary infections. 2.s-7,~ Pulmonary infection with mycobacterium tuberctdosis is a common infection in overcrowded areas. ~3 Mycobacteria other than M. tuberctdosis (atypical mycobacteria) also produce disease in man and presently are being discovered more frequently in association with individuals who exhibit Acquired Immune Deficiency Syndrome (AIDS). Some pulmonary organisms previously uncommon are more prevalent in the compromised cancer patient. One example is pneumocystis carinii, a protozoan, that was primarily associated with ill or premature infants. P. carhfii now infects an estimated 65% to 85% of all persons with AIDS. ~4 Pneumonia, superimposed on a cancer diagnosis, is a major cause of death in individuals with cancer. At least 50% of all cancer occurs in individuals over the age of 6515; therefore, many of the affected individuals may have already experienced alterations in pulmonary anatomy and/or physiology prior to malignant changes. In addition, normal structural and functional changes that are associated with the aging process compromise air intake in the elderly. Environmental, occupational, and social factors may have carcinogenic qualities, as well as an impact on the outcomes of the superimposed malignant process by initiating inflammatory processes and fibrotic changes in lung tissue that result in decreased lung compliance and diffusion defects. ~6 For example, asbestos is known to induce mesothelioma, lung cancer, and possibly colon cancer. Exposure to asbestos is known to enhance carcinogenic processes in persons who smoke. 17 Excess alcohol consumption is related to many cancers involving the upper respiratory airways. Nasal airway cancers are related to exposure to isopropyl alcohol and wood dusts. Lung cancers are associated with exposure to arsenic (ie, pesticides), nickel (nickel refiners), and polycyclic hydrocarbons associated with mineral oil and tar workers.IS Cigarette smoking, the major single unnecessary and preventable cause of illness and early death in the United States, is associated with cardiovascular disease, cerebral vascular accidents, emphysema, chronic bronchitis, and other chronic health problems, w Smoking is related to cancers of the larynx, oral cavity, and esophagus, all significant in the ventilatory processes, and also to cancers of the urinary bladder, kidney, pancreas, and cervix, w Approximately 90% of all lung cancer, 30% of all cancer deathsfl 6 and 25% of deaths from cardiovascular disease ~9 can be attributed to smoking. Needless to say, a smoking history is pertinent to both concurrent health care issues or problems of the person with cancer as well as to etiology of the cancer. 2°