Chapter 14 Lecture

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Cancer

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Learning Objectives

• Define cancer• Discuss the incidence of cancer in the United States• List the most common types of cancer• Identify factors that influence your risk of developing

cancer• Discuss several types of occupational carcinogens• Outline ways to reduce your risk of skin cancer due to

exposure to ultraviolet light• Discuss the roles of diet and exercise in reducing cancer

risk• Explain how free radicals increase your risk of cancer

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Cancer

• Second leading cause of U.S. deaths • A collection of over 100 related diseases characterized by

rapid, uncontrolled cell growth/often forms tumors • Can occur in almost any tissue/organ• Two kinds of tumors

– Benign (slower growing, less serious health threats)– Malignant (fast growing, very serious health threats)

• Biopsy: procedure determining type of cells• Metastasis: spread of cancer cells through body• Cancer cells invade other tissues and/or interfere with

organ functions, can lead to organ failure/death• Key to treatment/survival: early detection

Complete Lab 14.1: Determining Your Cancer Risk

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Early Cancer Detection: 7 Warning Signs

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Cancer Growth and Metastasis

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Cancer Cell Growth

• Controlled by DNA– DNA damaged by carcinogens– Uncontrolled cell growth occurs

• Carcinogens include– Radiation– Chemicals– Drugs– Toxic substances

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Cancer Cell Formation

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Types of Cancer

Lung Cancer• Leading cause of all cancer deaths• Easiest way to reduce risk: don't smoke

Colon and Rectal Cancer (Colorectal)• Third leading cause of cancer deaths •Get regular screenings for polyps after age 50

Breast Cancer•Most common cancer in women, second cause

of cancer deaths in women•Get mammograms/perform breast self-

examination

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Types of Cancer (cont.)

Prostate Cancer• Second leading cause of cancer deaths in men• Get regular exams, especially after age 50

Testicular Cancer• Most common cancer in young men• Perform routine self-examinations

Skin Cancer• Most common type of cancer• Two types: Melanoma and nonmelanoma• Avoid UV light and tanning beds• Wear sunscreen SPF 15 or higher

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Types of Cancer (cont.)

Uterine, Ovarian, and Cervical Cancer• Uterine: endometrial most common • Ovarian risk factors

– Age, obesity, longer menstrual history, genetics, infertility, breast cancer

• Cervical linked: human papillomavirus (HPV)

Other Cancers• Oral cancer

– Affects lips, mouth, throat, and tongue– Associated with tobacco and alcohol use

• Leukemia– Cancer of the blood

• Pancreatic cancer– Fourth leading cause of cancer deaths

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U.S. Cancer Death Rates

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Detecting Skin Cancer

Examine moles monthly using the ABCD rule• A: Assymetry (one half does not look like the other half)• B: Border (irregular, notched, or ragged)• C: Color (differing shades, patches)• D: Diameter (larger than 6mm, growing)

Not all skin cancers fit ABCD rule• Check moles/skin lesions regularly for any changes• Establish a baseline

Other Warning Signs• A sore that does not heal• New growth of any kind• Spread of pigment • Redness or swelling beyond the border• Change in sensation on the skin

Complete Lab 14.2: Early Detection

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Uncontrollable Cancer Risk Factors

Heredity• Having a close relative with diagnosed cancer

increases risk three-fold• Learn your family's health history (blood

relatives)• If hereditary risk exists, start screenings

sooner and get screenings more oftenRace

• Blacks have higher overall cancer rates than whites, death rates have been declining

• Increased awareness and early detection is critical

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U.S. Cancer Risk—Racial Diversity

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Controllable Cancer Risk Factors

Diet • Most important behavioral factor• Avoid high-fat, salt-cured, smoked, and nitrite-cured

foods• Eat foods rich in high-fiber and antioxidants (vitamins

A, E, and C)Alcohol Use

• Moderate drinking increases risk for some cancers• Eliminate/limit both frequency and amount

Tobacco Use• Single largest cause of cancer deaths• Risk: lifetime exposure to smoke, including second-

hand• Stopping at any time decreases your risk

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Controllable Cancer Risk Factors (cont.)

Physical Inactivity• Regular exercise protects against cancer in multiple ways

– strengthens immune system; helps maintain a healthy weight; positive effects on hormone levels; increases bowel motility

Exposure to Ultraviolet Light• Common UV sources are sunlight, tanning booths, sunlamps• Risk: cumulative exposure, not just occasional overexposure• Limit sun exposure, avoid tanning salons/wear sunscreen daily

Exposure to Viruses• Can invade cells/damaged DNA = blood, lymphatic, liver,

cervical, nose, pharynx cancer• To avoid HPV/cervical cancer: abstain from sex, use condoms,

limit number of partners

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Physical Fitness and Cancer Risk

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Controllable Cancer Risk Factors (cont.)

Radiation Exposure• Sources: medical X-rays, computer monitors, electric

blankets, cell phones• Take precautions/avoid or limit exposure

Occupational Carcinogens• Sources: industrial chemicals, asbestos, coal tars,

auto paints, herbicides, pesticides• Follow safety precautions/avoid exposure to industrial

agents• Contact EPA with questions: chemical exposure/

information

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ABC News: Tanning Beds

Discussion Questions

1. Why do you think some people become fixated on having a tan? In what ways do you think the media influence our society in terms of why many people feel the need to be tanned?

2. Were you surprised by the answers the tanning salon clerks gave when asked about the risk of tanning beds and cancer? Why or why not? In what ways do tanning beds increase your risk of skin cancer?

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ABC News: Tanning Beds cont

Discussion Questions

3. What do you know about vitamin D? Discuss the myth of getting vitamin D from tanning beds and what Dr. Oz suggests are the best ways to get it.

4. What alternatives can you think of to tanning in a tanning bed? What kinds of products are available today that offer safer ways to get a tan?

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ABC News: Mammogram Controversy

Discussion Questions

1. What is the controversy over when women should start getting mammograms? What dangers are posed for women on both sides of the debate?

2. What stances do breast cancer experts Susan Love and Marisa Weiss take in regard to new mammogram regulations? What pros and cons can you find on either side of the debate?

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ABC News: Treating Cancer with Bone Drugs

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ABC News: Possible Melanoma Treatment

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ABC News: Alcohol and Cancer

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Summary

• Cancer is the #2 cause of death in the United States

• Cancer is the uncontrolled growth and spread of abnormal cells. Groups of abnormal cells can form a tumor, which can be classified as benign or malignant

• Carcinogens are cancer-causing agents. Normal cells become cancerous when DNA becomes damaged by carcinogens, resulting in uncontrolled cell division

• Common sites of cancer include the breasts, lungs, colon, prostate gland, cervix, testes, pancreas, and mouth

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Summary (cont.)

• Heredity and race are non-modifiable risk factors for cancer

• Modifiable behavioral risk factors for cancer include exposure to carcinogens (such as radiation, viruses, tobacco, alcohol, occupational carcinogens, and ultraviolet light), eating a low-fiber diet, and being physically inactive

• Diet is probably the most important factor in controlling your risk of cancer

• Exercise has been shown to reduce the risk of cancer

• Participation in cancer screenings is important for early detection of cancer