Prevention

Prevention

Quitting smoking, eating a healthy diet, and avoiding excess sun exposure have all been shown to reduce cancer risk. Declining use of tobacco, in particular, is a major factor in the rate of new cancer cases in the United States decreasing by 10 percent since peaking in the early 1990s.

In addition to lifestyle changes, researchers are discovering a growing number of biomedical tools to prevent cancer, including preventive drugs and surgery for women at high risk of breast or ovarian cancer; removal of precancerous polyps for colorectal cancer; and vaccines to prevent the viruses that cause cervical, head and neck, and liver cancers.

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1998

Common obesity complication linked to liver cancer

Common obesity complication linked to liver cancer

Researchers begin to link non-alcoholic steatohepatitis, or NASH, to increased liver cancer risk. NASH involves inflammation and fat accumulation in the liver that is usually caused by obesity or diabetes. NASH develops in as many as 95 percent of people with morbid obesity and type 2 diabetes. One study estimates that just over 10 percent of liver cancer cases in the U.S. are caused by NASH. These findings point to important new ways to reduce the risk of liver cancer through diet, exercise and effective management of diabetes.

Treatment guidelines highlight obesity-cancer link
Drug therapy can reduce breast cancer risk in women at high risk

Drug therapy can reduce breast cancer risk in women at high risk

Badge indicating that research was paid for using federal funds

The FDA approves tamoxifen (Novaldex), a hormonal drug already used to prevent recurrence of breast cancer, to reduce the risk of developing breast cancer in women who are at high risk for the disease. The approval is based on a large trial showing that tamoxifen reduced breast cancer risk by more than 40 percent in women with a strong family history of breast cancer or with mutations in the BRCA1 and BRCA2 genes. Later research shows that a different drug used to treat osteoporosis, raloxifene (Evista), is as effective as tamoxifen at preventing invasive breast cancer, but with a lower risk of certain side effects.

1993

Bacterial infection linked to gastric cancer risk

Bacterial infection linked to gastric cancer risk

Badge indicating that research was paid for using federal funds

Researchers show a strong correlation between the incidence of stomach cancer and infection with a bacterium called H. pylori. Further studies estimate a 3- to 6-fold increased risk of stomach cancer for people infected with the bacteria.

H. pylori is spread through contaminated food, water and direct mouth-to-mouth contact. The U.S. Centers for Disease Control and Prevention estimates that approximately two-thirds of the world's population carries the bacterium, with infection rates being highest in developing countries. However, the bacterium does not cause illness in the majority of carriers.

In Western Europe and the United States, declining rates of H. pylori infection are thought to partly account for declines in stomach cancer cases in recent decades.

1992

Cigarette smoking and alcohol are conclusively linked to certain pharyngeal cancers

1988

Benzene discovered to cause blood cancers

Benzene discovered to cause blood cancers

Badge indicating that research was paid for using federal funds

Scientists find that occupational exposure to benzene, a chemical commonly used as a solvent and in oil-related products, is associated with increased risk of developing non-lymphocytic leukemia, non-Hodgkin lymphoma, and other diseases. Following this discovery, workers begin taking steps to protect themselves from benzene exposure and reduce their cancer risk.

1986

Second-hand smoke formally declared a carcinogen

1982

Research links sun exposure to melanoma risk

Research links sun exposure to melanoma risk

A growing number of studies in this period suggest that sun exposure plays an important role in the development of some melanomas. Specifically, frequency and duration of exposure, as well as a history of severe sunburn, are found to be associated with a person's risk of the disease. In the 1980s, the public health community and advocacy groups such as the Skin Cancer Foundation begin cautioning the public about the potential risks of sun exposure.

1981

First cancer vaccine prevents cancer-causing hepatitis B infection

First cancer vaccine prevents cancer-causing hepatitis B infection

The FDA approves the first vaccine against hepatitis B, one of the primary causes of liver cancer. In 1991, the U.S. begins routine vaccination of all children against hepatitis B, and by 2007, the number of acute hepatitis B cases among children under 15 years declines by 98 percent. Over time, routine vaccination is expected to reduce rates of liver cancer in the U.S. and globally among adults who were vaccinated as children.

Oral contraceptives found to cut ovarian cancer risk

Oral contraceptives found to cut ovarian cancer risk

Badge indicating that research was paid for using federal funds

Studies first begin suggesting that oral contraceptive use lowers the risk of developing ovarian cancer. Evidence continues to accumulate over the coming years, and in 2008, a review of 45 published studies concludes that "the pill" lowers ovarian cancer risk by 20 percent for every five years it is used. Authors of the 2008 study estimate that oral contraceptives had prevented some 200,000 ovarian cancers and 100,000 deaths worldwide in the 50 years since oral contraceptives were introduced, and may currently prevent 30,000 new cases of ovarian cancer each year.

1975

Use of cancer-causing asbestos declines

Use of cancer-causing asbestos declines

As studies confirm long-suspected links between asbestos and certain cancers, use of asbestos begins to decline. In the 1980s, its use is banned in a growing number of applications, and environmental and health regulations help to dramatically limit exposure to asbestos in workplaces and homes. Asbestos exposure has been shown to increase a person's risk of lung cancer, mesothelioma (an aggressive cancer in the chest or abdomen), and other serious health problems. Because these problems often occur decades after exposure, however, the impact of preventive efforts will be felt gradually in the years ahead.

1974

Cigarette smoking linked to bladder cancer risk

Cigarette smoking linked to bladder cancer risk

Researchers tie sharp increases in bladder cancer deaths among British men to the rapid rise in cigarette smoking during prior decades. Because smoking gained popularity more slowly among women, comparable increases in bladder cancer deaths take longer to emerge.

Years later, in 2011, researchers from the U.S. National Cancer Institute report that cigarette smokers have four times the risk of bladder cancer as non-smokers. Overall, the study attributes about half of U.S. bladder cancer cases to smoking.

Warning labels first appear on cigarette packs

Warning labels first appear on cigarette packs

Researchers tie sharp increases in bladder cancer deaths among British men to the rapid rise in cigarette smoking during prior decades.  Because smoking gained popularity more slowly among women, comparable increases in bladder cancer deaths take longer to emerge.

Years later, in 2011, researchers from the U.S. National Cancer Institute report that cigarette smokers have four times the risk of bladder cancer as non-smokers.  Overall, the study attributes about half of U.S. bladder cancer cases to smoking.

Tobacco use found to cause pancreatic cancer

1962

Hepatitis B, a leading cause of liver cancer, is discovered

1959

Smoking linked to cancer; cessation campaigns begin

Smoking linked to cancer; cessation campaigns begin

In the 1950s, studies begin to show that smoking is a major cause of cancer, particularly lung cancer. In the early 1960s, both the U.S. Surgeon General and the U.K. Royal College of Physicians issue reports linking smoking to cancer and other serious health problems. In later years, smoking is also established as a major cause of pancreatic cancer, and second-hand smoke is declared a threat to the health of non-smokers. Tobacco control and smoking cessation soon become the most important strategies for reducing the worldwide toll of lung cancer.