Lung cancer is a disease in which cancer cells grow in the lungs.
Lung cancer occurs when cells in the lung divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms, called a growth or tumor. The term cancer refers to malignant tumors, which can invade nearby tissues and can spread to other parts of the body. A benign tumor does not invade or spread.
Lung cancers that start in the lungs are divided into two types:
Non-small cell lung cancer –
generally grows and spreads more slowly. This accounts for about 75% of the lung cancers diagnosed each year in the United States.
The most common types of non small cell lung cancer are squamous cell cancer and adenocarcinoma.
Small cell lung cancer –
generally grows more quickly and is more likely to spread to other parts of the body. This accounts for about 25% of the lung cancers diagnosed each year.
Lung cancer is caused by exposure to cancer-causing substances. Most cases are associated with tobacco use. Causative agents include:
- First- or second-hand cigarette smoke
- Pipe or cigar smoking
- Radon – an invisible, odorless, and tasteless radioactive gas in soil and rocks. Radon can be found in most parts of the country. It can seep through the foundations or slabs and accumulate in the air inside buildings. ÔThe EPA recommends that homes be tested for elevated radon levels and steps taken to reduce the levels when an increase is found.
- Asbestos – a group of minerals that occur naturally as fibers and are used in certain industries, particularly building, brake fabrication, and shipyard industries. Asbestos can be carried home on the clothes of an exposed worker and cause illness in family members.
- “Scar” cancers may arise from areas of previous lung damage, such as that produced by tuberculosis, which causes scarring in the lungs.
More Americans, men and women, die of lung cancer than any other cancer. According to the American Cancer Society, about 154,900 people will die annually from this form of cancer, which is higher than those who die from colon, breast, and prostate cancer combined. This year, about 169,400 Americans will learn they have lung cancer.
