Major Forms of Cancer - Lung cancer

Lung cancer kills more Americans than any other cancer. The average annual death toll for recent years is more than 90,000 men and more than 45,000 women. It represents 36 percent of all cancers in men, 20 percent of all cancers in women. There has been a dramatic increase in the incidence of lung cancer in women over the past 35 years to where it has surpassed breast cancer as the leading cause of cancer death among women. The five-year survival rate for this disease is between 10 and 20 percent.

Symptoms

Although some early lung cancers do not show up on an X-ray film, they are the ones that usually produce coughing as an early symptom. For this reason, any cough that lasts more than two or three weeks—even if it seems to accompany a cold or bronchitis—should be regarded as suspicious and investigated in that light. Blood in the sputum is another early warning sign that must be investigated immediately; so should wheezing when breathing. Later symptoms include shortness of breath, pain in the chest, fever, and night sweats.

Detection

If many lives could be saved by preventing lung cancer in the first place, others could be saved by early detection. By the time most lung cancers are diagnosed, it is too late even for the most radical approach to cure—removal of the afflicted lung. Experts estimate that up to five times the present cure rate could be achieved if very early lung cancers could be spotted. They therefore recommend a routine chest X ray every six months for everyone over 45.

Causes

Lung cancer is one of the most preventable of all malignancies. Most cases, the majority of medical experts agree, are caused by smoking cigarettes. The U.S. Public Health Service has indicted smoking as “the main cause of lung cancer in men.” Even when other agents are known to produce lung cancers—uranium ore dust or asbestos fibers, for example—cigarette smoking enormously boosts the risk among uranium miners and asbestos workers. Smoking accounts for 90 percent of all lung cancer deaths.

It is known that the lungs of some cigarette smokers show tissue changes before cancer appears, changes apparently caused by irritation of the lining of the bronchi —the, large air tubes in the lung. Physicians believe these changes can be reversed before the onset of cancer if the source of irritation—smoking—is removed. This is why a heavy smoker who has been puffing away for many years but then stops smoking has a better chance of avoiding lung cancer than one who continues smoking.

Until recently, the evidence linking cigarette smoking and lung cancer was purely statistical, although overwhelming. No one had succeeded in producing lung cancer in laboratory animals by having them ingest smoke. However, lung cancer has been induced in dogs specially trained to inhale cigarette smoke, as reported by the American Cancer Society.

Cigarette smoking has also been implicated in other kinds of lung disease, including the often-fatal emphysema, and in cardiovascular diseases. To any sensible person, then, the options would seem clear: If you don't smoke, don't start. If you do smoke, stop. If you can't stop, cut down, and switch to a brand low in tars and nicotine—suspected but not proved to be the principal harmful agents in cigarette smoke.