Respiratory cancers and pollution.

BACKGROUND: Cancer is the major public health problem worldwide, irrespective of the socio-economic status of the countries. Even though the overall mortality from cancer is higher in the western countries, the cancer burden is on the rise in under-developed countries, with a projected 81-100% increase by 2030, mostly due to pollution and tobacco use. Respiratory cancers affect the lung, larynx, trachea, and bronchus and depending on the location of the cancer, the symptoms change and also the risks, incidence and survival outcomes differ accordingly. Besides tobacco use, chronic exposure to household pollution is known to be associated with elevated risk of lung cancer and other cancers. Women and children living in severe poverty in the underdeveloped countries are exposed most to household air pollution and, thus, suffer its consequences maximally, and household air pollution, specifically arising from solid fuel burning, which accounts for nearly 4 million deaths throughout the world annually. Cancers affecting the respiratory tract, including both nasopharyngeal cancer and lung cancer, are strongly associated with pollution from coal and other solid fuel burning. Lung cancer, which is of two types, small cell lung carcinoma and the non-small cell lung cancer, is the most common and fatal cancer. Even though tobacco has been viewed as the major risk for respiratory cancers, it is now evident that household pollution, exposure to asbestos, chromium and arsenic etc, all pose a significant risk for respiratory cancers. Preventive steps to curtail the many sources of air pollution by improving living conditions and reducing the occupational exposure hazards like welding, industrial work etc., are markedly needed to control the incidence of respiratory cancers.