Pulmonary tumors may be primary or secondary and benign or malignant. Their cause is unknown, but a statistical relationship exists between cigarette-smoking and lung cancer. Primary carcinoma of the lung is responsible for 5 to 10% of all deaths from cancer and the disease is steadily increasing in frequency. It is more common in men though the incidence is increasing in women. Most cases occur between ages 40 to 70. The clinical presentation depends on the nature of the tumor and its location. The patient may be asymptomatic if the tumor is in a "silent" area; 90% of patents with primary carcinoma of the bronchus complain of a cough and in 50% it is the first symptom. In patients who already have a chronic cough, an alteration in its character or severity may cause suspicion. A localized wheeze indicates partial obstruction of a bronchus. Obstruction of a large broncus causes shrinkage of chest wall and diminution of chest movement and breath sounds. Sputum is often scanty and mucoid unless an infection (pneumonitis or lung abscess) occurs . Sever, constant, nonpleuritic pain is a peculiar and not infrequent manifestation. Not infrequently, an inapparent bronchogenic carcinoma may first manifest itself in a remote metastasis, especially in the brain. In advanced disease, the patient may present with nonspecific symptoms such as weight loss, anorexia, and weakness. Intrathoracic extension of the tumor may produce pleuritis, often with pleural effusion: hoarseness due to involvement of the recurrent laryngeal nerve. Diagnosis involves not only detection and classification of the tumor but also determination of the extent of its spread and its operability. Often the chest x-ray is the only abnormality in an asymptomatic patient and thus it provides the greatest likelihood of early diagnosis. In addition to the tumor, the chest x-ray may show signs of bronchial obstruction such as overinflation or infection, elevation of the diaphragm. About 60 to 70% of cases of bronchogenic carcinoma can be diagnosed from sputum cytology. The diagnosis is usually established by bronchoscopy, either by direct visualization and biopsy of the tumor or by examination of bronchial washings. A thoracotomy and biopsy may be necessary to establish the diagnosis in some cases. The average survival time of patents with untreated carcinoma of the bronchus is 9 months. The overall 5-yr survival rate is less than 10%. Cigarette smoke contains more than 4,000 different chemicals, many of which are carcinogens (may cause cancer). The three of the most damaging toxins are nicotine, tars, and
. Second-hand smoke inhaled by both smokers and nonsmokers is another important cause of lung cancer. Smoking is responsible for 90% of lung cancer deaths among men, 79% among women. Also smoking accounts for about 30% of all cancer deaths. Smokers that inhale two or more packs of cigarettes a day, have a cancer mortality rate 12-25 times greater than a nonsmokers. The risk of lung cancer falls dramatically within a couple years if smoking is stopped. Radon is the second leading cause of lung cancer. It is a radioactive gas found in the earth's rocks and soil, formed by the natural breakdown of radium. Excessive exposure of radon in the home may increase the risk of lung cancer especially in smokers. If the radon levels are found to be to high, remedial actions should be taken. Another cause of cancer is on the job exposure to carcinogens. The best known carcinogen is asbestos. Others include nickel, chromate, and vinyl chloride.