According to the World Health Organization, tobacco is the single most common cause of cancer in the world today. In the U.S., the American Cancer Society estimates that about 30 percent of all cancer deaths are caused by tobacco use, principally cigarette smoking. They estimate that a smoker is exposed to 4000 toxic chemicals in cigarette smoke, of which 60 are known human carcinogens. Several types of cancers in different systems of the body are attributable to cigarette smoking.
Respiratory System Cancers
Lung cancer is the leading cause of cancer death in the U.S. and, according to the Centers for Disease Control, about 90 percent of all lung cancers in the U.S. take place in cigarette smokers. The 2004 Surgeon General's report states that cigarette smoking increases the risk of developing lung cancer 23 times in men and about 13 times in women.
Cigarette smoking, encouraged by alcohol use, is also implicated in laryngeal cancer, involving the voice box. Other cancers of the respiratory system linked to cigarette smoking are cancer of the nasal cavity, cancer of the sinuses and cancer of the pharynx, or throat.
Digestive System Cancers
The digestive system is not spared. The Surgeon General's report of 2004 names cigarette smoking as a major cause of esophageal cancer, involving the tube that connects the mouth to the stomach. There was a reduction in the incidence of stomach cancer among people who stopped smoking as opposed to those who continued to smoke.
Other cancers of the digestive system attributable to cigarette smoking are cancers of the oral cavity--mouth, tongue, lips--and the pancreas.
Urogenital System Cancers
Cancers of the urogenital system implicated in cigarette smoking include cancer of the kidneys and bladder.
Reproductive System Cancers
According to the CDC, the risk of developing cervical cancer increases with the duration of the smoking habit. Another reproductive cancer linked to cigarette smoking is cancer of the uterus, or endometrial cancer.
Other Cancers
Cigarette smoke contains benzene, a highly toxic chemical known to cause acute myeloid leukemia, a cancer of the white blood cells. According to the Surgeon General's report, 90 percent of a smoker's exposure to benzene comes from cigarette smoke.
A recent finding at the National Institutes of Health shows that recurrence of breast cancer is more common in smokers than in nonsmokers. There was significantly increased risk in developing a second tumor in the same breast as well as developing a cancer in the breast previously unaffected by cancer.
References
- World Health Organization: Cancer Prevention
- American Cancer Society: Cigarette Smoking
- Centers for disease control and prevention: Health Effects of Smoking Cigarettes
- American Cancer Society: Tobacco-Related Cancer Factsheet
- National Institutes of Health/MedlinePlus: Smoking Ups Risks For Second Breast Cancer
