Lung

A clear dose-response relationship exists between lung cancer risk and daily cigarette consumption. From 1950 to 1990, the U.S. mortality rate for lung cancer increased fourfold for men and sevenfold for women. Although the mortality rates in men have been declining since 1990, lung cancer is still the principal cause of cancer death for both genders.

Lung and bronchus

Leukemia

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Year of death

Lung and bronchus

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Figure 50-3 A, Annual age-adjusted cancer death rates among males for selected cancers, United States, 1930-2005 (rates are age-adjusted to the 2000 U.S. population). Because of changes in International Classification of Disease (ICD) coding, numerator information has changed over time. Rates for cancers of the lung and bronchus, colon and rectum, and liver are affected by these changes. B, Annual age-adjusted cancer death rates among females for selected cancers, United States, 1930-2005 (rates are age-adjusted to the 2000 U.S. standard population). *Uterus includes uterine cervix and uterine corpus. Because of changes in ICD coding, numerator information has changed over time. Rates for cancers of the uterus, ovary, lung and bronchus, and colon and rectum are affected by these changes. (A from US mortality data, I960 to 2005, US Mortality 1930-1959. National Cancer Institute, CDC, 2008. CA Cancer J Clin 59:233, 2009; B from US mortality data, 1960 to 2005, US Mortality I930-I959, National Center for Health Statistics, CDC, 2008. CA Cancer J Clin 59:234, 2009.)

In 1988, lung cancer passed breast cancer as the leading cause of death from cancer in women (Fig. 50-3). Although the lung cancer death rate has leveled off in U.S. women, in some states it is still increasing (Fig. 50-4).

Unfortunately, early detection does not improve the survival rate for lung cancer. The 5-year survival rate is only 15%

and has improved only slightly since the early 1960s (ACS, 2005). Almost 60% of lung cancer patients die within a year and 85% within 5 years. By the time the diagnosis is made, three of four patients already have metastases. However, the risk of death from lung cancer is substantially reduced when smoking is discontinued. Reducing smoking from an average

MALES FEMALES

Year of death Year of death

Figure 50-4 Trends in age-standardized lung cancer death rates for the United States and select states by gender, 1975-2005. (From Cokkinides V et al. CA Cancer J Clin 59:357, 2009.)

of 20 cigarettes a day to less than 10 per day reduces the lung cancer risk by 25% (Godtfredsen et al., 2005). A diminished risk for lung cancer is experienced in former smokers after 5 years of cessation; however, the risk remains higher than that of nonsmokers for as long as 15 to 20 years (US Surgeon General, 2004).

Although the amount of tar in cigarettes has declined in recent years, the risk of lung cancer has not changed. Smoking formerly labeled "low-tar" and "low-nicotine" cigarettes provides no benefit over smoking regular cigarettes, and the uptake of carcinogens is no different in "regular," "light," and "ultralight" smokers (Hecht et al., 2005), as previously marketed. However, surveys show that most people believed "light" cigarettes to be less dangerous than regular cigarettes and regular cigarettes much more likely to cause illness. The recent federal legislation banning the use of words such as "light" from tobacco advertising is beginning to dispel this myth.

Increasing data regarding the genetic predisposition to lung cancer are emerging (see Smoker's Genetics). Family aggregation related to lung cancer is likely multifactorial, including exposure to secondhand smoke, major genetic factors (e.g., chromosome 6p locus, CYP1A1 gene), other genes that modify risk of lung cancer, and genes that may enhance nicotine addiction or modify nicotine metabolism (D'Amico, 2008; US Surgeon General, 2004).

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