Cancer Basics and Definition

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Questions and Answers

What proportion of Americans die of cancer, according to the American Cancer Society?

One in five

What are the three leading sites of new cancer cases for American men, excluding skin cancer?

Prostate, lung, and colon and rectal (colorectal) cancers

What is responsible for most cancer deaths in the United States?

Lung cancer

What type of damage to cells leads to the development of cancer?

Damage to certain genes (mutations) Signup and view all the answers

What proportion of cancer deaths are preventable?

A significant number Signup and view all the answers

What is the focus of this section of the chapter?

The roles of diet and exercise in the development, progression, and possible prevention of certain cancers Signup and view all the answers

Where can readers find more information about cancer, including specific forms of cancer?

The American Cancer Society’s website at <a href="http://www.cancer.org">www.cancer.org</a> or the National Cancer Institute’s website at <a href="http://www.cancer.gov">www.cancer.gov</a> Signup and view all the answers

What is cancer defined as?

A group of chronic diseases characterized by cells that have undergone damage to certain genes (mutations) Signup and view all the answers

What is the primary function of genes in cellular development?

Genes code for the production of specific proteins that regulate cellular growth, division, and death. Signup and view all the answers

How do malignant cells differ from healthy cells in terms of growth and division?

Malignant cells divide repeatedly and frequently, and they do not die, unlike healthy cells that grow, divide, and die in a controlled fashion. Signup and view all the answers

What is the result of genes regulating cellular growth, division, and death mutating?

Abnormal cell development, rapid cell growth, and unchecked cell division can result. Signup and view all the answers

What is metastasis, and how does it occur?

Metastasis is the spread of cancer to other tissues, and it occurs when malignant cells break away from the tumor and invade other parts of the body. Signup and view all the answers

What is the difference between benign and malignant tumors?

Benign tumors are not cancerous, do not destroy nearby tissues, and do not metastasize, whereas malignant tumors are cancerous and can invade other tissues. Signup and view all the answers

What is a carcinogen, and how does it contribute to cancer development?

A carcinogen is an environmental factor that triggers cancer, and it can irritate tissues, causing inflammation, and damage DNA, leading to mutations. Signup and view all the answers

Why is a healthy immune system important in preventing cancer?

A healthy immune system identifies and destroys malignant cells before they multiply uncontrollably. Signup and view all the answers

Why do malignant cells require more nutrients than normal cells?

Malignant cells require more nutrients due to their rapid growth and frequent cell divisions. Signup and view all the answers

What is the importance of early diagnosis in cancer treatment?

Early diagnosis of cancer is critical because it allows for effective treatment before the cancer metastasizes. Signup and view all the answers

Why do some smokers develop lung cancer and others not?

Smokers who develop lung cancer likely have genetic mutations or other factors that increase their susceptibility to the carcinogenic effects of tobacco smoke. Signup and view all the answers

What percentage of cancers occur in people over 55 years of age?

80% Signup and view all the answers

What is responsible for many cases of lung cancer, as well as other types of cancer?

Tobacco use Signup and view all the answers

What is estimated to be responsible for 18% of cancers that occur in the United States?

Poor diet, alcohol consumption, physical inactivity, and excess body fat Signup and view all the answers

What is the effect on cancer risk when Asian men and women migrate to Western countries?

Their risks of prostate and breast cancer increase and eventually become similar to the risks of their adopted country’s native population. Signup and view all the answers

What is the recommended daily limit of alcoholic drinks to reduce the risk of cancer?

No more than one standard drink per day for women and no more than two standard drinks per day for men Signup and view all the answers

What type of cancer is associated with consuming foods contaminated with aflatoxin?

Liver cancer Signup and view all the answers

What type of meat is associated with an increased risk of colorectal and prostate cancer?

Processed meat and/or red meat Signup and view all the answers

What chemicals added to processed meat during production can form nitrosamines, which are carcinogens?

Sodium nitrate and sodium nitrite Signup and view all the answers

How many Americans were predicted to die in 2020 as a result of smoking cigarettes?

Just under 182,000 Signup and view all the answers

What percentage of cancer deaths in the United States are associated with smoking tobacco?

Approximately one of every four Signup and view all the answers

How does adequate fluid intake reduce the risk of cancer?

Adequate fluid intake encourages frequent urination, which reduces the time that carcinogens remain in contact with the walls of the bladder. Signup and view all the answers

What role do antioxidants play in cancer prevention?

Antioxidants protect DNA from free radical damage, preventing potentially cancer-causing mutations from occurring. Signup and view all the answers

What is the suspected link between consumption of smoked or salt-preserved foods and stomach cancer?

Increased risk of stomach cancer Signup and view all the answers

What is the concern with taking antioxidant supplements?

Taking antioxidant supplements may increase the risk of lung and prostate cancers, especially among smokers and men with family histories of prostate cancer. Signup and view all the answers

What are heterocyclic amines and how are they related to cancer?

Heterocyclic amines are carcinogens formed during high-temperature cooking; their impact on human cancer risk is unclear. Signup and view all the answers

How do phytochemicals in plant foods help reduce cancer risk?

Phytochemicals inhibit tumor growth by being toxic to cancer cells, interfering with their ability to form supportive blood vessels, or creating conditions that make it difficult for cancer cells to flourish. Signup and view all the answers

What is the relationship between excess body fat and cancer development?

Excess body fat is linked to higher risks of certain cancers, possibly due to elevated hormone levels. Signup and view all the answers

What is the current understanding of the cancer-protective benefits of phytochemicals?

Much of the evidence about the cancer-protective benefits of specific plant-based chemicals is from laboratory experiments on animals or cell cultures. Signup and view all the answers

How does excess abdominal fat contribute to the risk of esophageal cancer?

Excess abdominal fat restricts stomach expansion, leading to acid reflux and chronic irritation of the esophagus. Signup and view all the answers

What lifestyle habit may reduce the risk of certain cancers, including colon and breast cancer?

Regular physical activity Signup and view all the answers

What dietary factor is associated with an increased risk of liver cancer?

Aflatoxin, found in moldy nuts and grains Signup and view all the answers

What are some ways to reduce the risk of cancer, according to the American Cancer Society?

Limiting alcohol consumption, achieving and maintaining a healthy weight, adopting a physically active lifestyle, and eating a healthy diet that limits intakes of red and processed meat and emphasizes intakes of plant foods, including fruits, vegetables, and whole grains. Signup and view all the answers

What is the possible mechanism by which excess calorie intake increases cancer risk?

Excess calorie intake leads to obesity, which may increase hormone levels, promoting cancer development. Signup and view all the answers

What is the role of physical activity in cancer prevention?

Physical activity may reduce cancer risk, although the exact mechanism is unclear. Signup and view all the answers

Why is it important to consume fiber-rich foods, including fruits and vegetables?

Fiber-rich foods may reduce the risk of cancer, and are rich sources of fiber and vitamin C, as well as carotenoids and other phytochemicals that may have antioxidant activity in the body. Signup and view all the answers

What is the current understanding of the relationship between diet and cancer risk?

People may be able to reduce their risk of many types of cancer significantly by improving their dietary choices and increasing their physical activity. Signup and view all the answers

What is the recommended intake of fluids in relation to cancer prevention?

Drinking enough water and other nonalcoholic fluids may reduce the risk of bladder cancer. Signup and view all the answers

What is the relationship between processed meat consumption and cancer risk?

Processed meat consumption is associated with an increased risk of cancer, possibly due to sodium nitrate and nitrite. Signup and view all the answers

Why is it important to follow the American Cancer Society’s recommendations for reducing cancer risk?

Following the American Cancer Society’s recommendations does not guarantee zero risk of cancer, but people may be able to reduce their risk of many types of cancer significantly by improving their dietary choices and increasing their physical activity. Signup and view all the answers

What is the suspected link between sodium nitrate and nitrite intake and cancer development?

Sodium nitrate and nitrite may form nitrosamines, which are carcinogenic. Signup and view all the answers

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Study Notes

Cancer Definition and Basics

Cancer is a group of chronic diseases characterized by cells that have undergone damage to certain genes (mutations)
Cancerous cells are out of control, dividing repeatedly and frequently, and not dying
When a cell becomes malignant, it does not perform the specialized functions of the cells from which it was derived
Malignant cells often break away from the tumor and can move to and invade other parts of the body, causing the disease to metastasize

Types of Tumors

Malignant tumors: form masses and can invade nearby tissues and metastasize
Benign tumors: are not cancerous, do not destroy nearby tissues, and do not metastasize

Causes of Cancer

Carcinogens: environmental factors that trigger cancer, such as radiation, tobacco smoke, or viruses
Genetics: inherited traits can increase the risk of certain cancers
Lifestyle factors: poor diet, physical inactivity, and excess body fat can increase the risk of certain cancers
Aging: 80% of cancers occur in people over 55 years of age

Cancer Sites and Deaths

Leading sites of new cancer cases in American men: prostate, lung, and colorectal cancers
Leading sites of new cancer cases in American women: breast, lung, and colorectal cancers
Lung cancer is responsible for most cancer deaths

Diet and Cancer

Diets that contain large amounts of processed meat and/or red meat are associated with increased risk of colorectal and prostate cancer
Consuming foods contaminated with aflatoxin can increase the risk of liver cancer
Eating high amounts of smoked or salt-preserved foods may increase the risk of stomach cancer
High temperatures used to fry, grill, or broil meat may cause the formation of carcinogens
Diets that provide a surplus of calories can lead to excess body fat, increasing the risk of certain cancers

Nutrition and Physical Activity Cancer Prevention

Consuming a nutritious diet with adequate fluids and a variety of foods, especially plant foods, may prevent or delay certain cancers
High intakes of fiber-rich foods, including fruits and vegetables, may reduce the risk of cancer
Phytochemicals in plant foods may have antioxidant activity, protecting DNA from free radical damage
Regular physical activity may reduce the risk of certain cancers by controlling weight, improving immune system functioning, and enhancing the body's regulation of various hormones

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