Lung Cancer

Asbestos Lung Cancer Among Workers

Studies show an increase in lung cancer among workers exposed to asbestos. This increase is particularly significant among asbestos–exposed workers who smoke. A dose–response relationship exists both for the degree of asbestos exposure and the amount of cigarette smoking. See Asbestos and Cigarettes.

Asbestos Lung Cancer Explained

Most asbestos lung cancer starts in the lining of the bronchi, the tubes into which the trachea or windpipe divides. However, asbestos lung cancer can also begin in other areas such as the trachea, bronchioles (small branches of the bronchi), or alveoli (lung air sacs). Although lung cancer usually develops slowly, once it occurs, cancer cells can break away and spread to other parts of the body.

The two most common types of lung cancer are small cell lung cancer (SCLC), in which the cancer cells are small and round, and non–small cell lung cancer (NSCLC), in which the cancer cells are larger. Sometimes a cancer has features of both types, and is called mixed small cell/large cell cancer.

Non–small cell lung cancer accounts for almost 80% of lung cancers. Small cell lung cancer accounts for about 20% of all lung cancers (American Cancer Society, Lung Cancer). Although the cancer cells are small, they can multiply quickly and form large tumors. The tumors can spread to the lymph nodes and to other organs.

Early–stage asbestos lung cancer may be asymptomatic (without symptoms). The methods used to diagnose asbestos lung cancer include imaging tests, biopsies, and taking phlegm (spit) samples.

Worldwide, lung cancer is the most common cancer in terms of both incidence and mortality with 1.35 million new cases per year and 1.18 million deaths, with the highest rates in Europe and North America. The population segment most likely to develop lung cancer is over-fifties who have a history of smoking. Lung cancer is the second most commonly occurring form of cancer in most western countries, and it is the leading cancer-related cause of death. Although the rate of men dying from lung cancer is declining in western countries, it is actually increasing for women due to the increased takeup of smoking by this group. Among lifetime non-smokers, men have higher age-standardized lung cancer death rates than women.

Not all cases of lung cancer are due to smoking, but the role of passive smoking is increasingly being recognized as a risk factor for lung cancer, leading to policy interventions to decrease undesired exposure of non-smokers to others' tobacco smoke. Emissions from automobiles, factories and power plants also pose potential risks.

Eastern Europe has the highest lung cancer mortality among men, while northern Europe and the U.S. have the highest mortality among women.Lung cancer incidence is currently less common in developing countries. With increased smoking in developing countries, the incidence is expected to increase in the next few years, notably in China and India.

Lung cancer incidence (by country) has an inverse correlation with sunlight and UVB exposure. One possible explanation is a preventative effect of vitamin D (which is produced in the skin on exposure to sunlight).