Cancer: Reducing Your Risk Chapter 16 Cancer: Reducing Your Risk

Objectives Understand what cancer is, how it develops, and its causes. Discuss ways to prevent cancer and the implications of behavioral risks. Describe the different types of cancer and the risks they pose to people at different ages and stages of life.

Objectives (cont.) Explain the importance of early detection, self-exams, medical exams, and symptoms related to different types of cancer. Discuss cancer diagnosis and treatment, including radiation therapy, chemotherapy, immunotherapy, and other common methods of detection and treatment.

An Overview of Cancer In 2008, approximately 565,650 Americans died of cancer. Each year, 1.5 million new cases are diagnosed. One-third of cancers are related to poor nutrition, physical inactivity, and obesity—preventable causes. The early Greek physicians who first described cancerous tumors were struck by the resemblance of these invasive tumors to crabs. So they termed them karkinos, or “crab” cells.

Copyright © 2010 Pearson Education, Inc.

What Is Cancer? Cancer is a large group of diseases characterized by the uncontrolled growth and spread of abnormal cells. Neoplasm is new growth of tissue that serves no physiological function. A tumor is a clumping of neoplasmic cells. Malignant means “cancerous.” Benign means “noncancerous.” A biopsy is a microscopic examination of cell development. The body is made of billions of small cells. Many cells make up organs such as lungs, heart, or bone. Usually when cells get old or damaged they die and are replaced by new cells. Sometimes cells continue to grow and divide when they are not needed, causing an abnormal growth called a tumor.

What Is Cancer? (cont.) Metastasis is the process by which malignant tumors that are not enclosed in a protective capsule spread to other organs. Mutant cells form after a disruption of RNA and DNA within normal cells, which may produce cells that differ in form, quality, and function from the normal cell. Cancerous cells may also spread to different parts of the body through direct invasion or through blood and lymph channels. Lymph is a nearly clear fluid produced by the body that drains waste from cells. It travels through special vessels and bean-shaped structures called lymph nodes. A cancer in the body is named according to where it began. Cancer that began in the lungs is called lung cancer, even if it spreads to another place such as the liver or the brain. Although doctors can locate a cancer’s origin, the cause of the cancer in a patient cannot usually be identified.

What Causes Cancer? External factors, such as chemicals, radiation, viruses, and lifestyle Internal factors, such as hormones, immune conditions, and inherited mutations Cellular change theory says cancer results from carcinogens. oncogenes. An estimated 75 to 85 percent of all deaths from cancer are related to environmental factors, or carcinogens. Oncogenes are suspected cancer-causing genes present on chromosomes.

Metastasis Copyright © 2010 Pearson Education, Inc.

Risks for Cancer Lifetime risk is the probability that an individual, over the course of a lifetime, will develop cancer or die from it. Relative risk is the measure of the strength of the relationship between risk factors and a particular cancer. Smoking is responsible for 30 percent of all cancer deaths and 87 percent of lung cancer deaths. Obesity increases risk to 50 percent for breast cancer in postmenopausal women, 40 percent for colon cancer in men. Cancer is a chronic disease. With chronic disease, risk factors, not causes, are examined. Risk factors are factors that have a high correlation with the development of the disease.

Tobacco Use in the United States, 1900–2003 Copyright © 2010 Pearson Education, Inc.

Copyright © 2010 Pearson Education, Inc.

Biological Factors Some cancers, such as breast, stomach, colon, prostate, uterus, ovary and lung, appear to run in families. Hodgkin’s disease and certain leukemias show similar patterns. Genes appear to account for approximately 5 to 10 percent of all cases of breast cancer.

Cancer Death Rates, by Race and Ethnicity, United States, 2000–2004 Copyright © 2010 Pearson Education, Inc. 14

Reproductive and Hormonal Risks for Cancer Pregnancy and oral contraceptives increase a woman’s chances of breast cancer. Late menarche, early menopause, early first childbirth, and having many children have been shown to reduce risk of breast cancer.

Leading Sites of New Cancer Cases and Deaths, 2008 Estimates Copyright © 2010 Pearson Education, Inc.

Occupational and Environmental Factors Asbestos Nickel Chromate Benzene Arsenic Radioactive substances Cool tars Herbicides and pesticides

Chemicals in Foods Sodium nitrate when ingested forms a potential carcinogen, nitrosamine. Sodium nitrate is still used because it is effective in preventing botulism. Pesticide and herbicide residues in high doses are known to cause cancer.

Social and Psychological Factors Stress has been implicated in increased susceptibility to several types of cancers. Sleep disturbances, diet, or a combination of factors may weaken the body’s immune system. Although psychological factors may play a part in cancer development, lifestyle habits such as tobacco use are believed to be far more important.

Infectious Disease and Cancers Herpes-related viruses may be involved in the development of leukemia, Hodgkin’s disease, cervical cancer, and Burkitt’s lymphoma. Epstein-Barr virus, associated with mononucleosis, may contribute to cancer. Human papillomavirus (HPV), a virus that causes genital warts, has been linked to cervical cancer. Helicobacter pylori causes ulcers, which are a major factor in the development of stomach cancer.

Medical Factors Some medical treatments actually increase a person’s risk for cancer. Diethylstilbestrol (DES) was used from 1940 to 1960 to control bleeding during pregnancy; the daughters of mothers who used DES were found to have an increased risk for cancers of the reproductive organs. Estrogen supplementation contributes to multiple cancer risks. Chemotherapy used to treat one form of cancer may increase risk for another type of cancer.

Types of Cancers Classification of cancers Carcinomas Sarcomas Lymphomas Leukemias Cancers are classified according to the type of cell and organ in which they originate: Carcinoma Carcinoma starts in the epithelium, the layer of cells that covers the body’s surface or line internal organs and glands. Is it the most common kind of cancer. Sarcoma Sarcoma forms in the supporting or connective tissues of the body: bones, muscles, and blood vessels. Leukemia Leukemia forms in the blood-forming tissues: bone-marrow, lymph nodes, and spleen. Lymphoma Lymphoma arises in the cells of the lymph system, or the network in the body that filters out impurities.

Lung Cancer In 2008, an estimated 161,840 people died from lung cancer. Since 1987, more women have died from lung cancer than breast cancer. Symptoms: persistent cough, blood-streaked sputum, and chest pain. Treatment: surgery, radiation therapy, and chemotherapy Prevention: avoid smoking and environmental tobacco smoke Lung cancer is the number one cancer killer of men and women. Most cases of lung cancer are related to cigarette smoking. If you smoke, stop as soon as possible.

Breast Cancer One in eight women will develop breast cancer in her lifetime. One in 210 between birth and age 39 One in 26 between ages 40 to 59 One in 15 between ages 60 to79 Detection: mammograms, regular breast self-exams Symptoms: lump in the breast, thickening, dimpling, skin irritation, distortion, tenderness Cancer of the breast is the most common form of cancer that affects women, but it is no longer the leading cause of cancer deaths in women. About one in ten women are diagnosed with breast cancer every year. Breast cancer originates in either the lobules or the ducts of the breast. If in the lobules, it is called lobular carcinoma. The lobules are the special milk-producing glands. When the cancer occurs in the ducts of the breast it is known as ductal carcinoma. When the cancer extends beyond the involved lobule or duct, it is known as invasive cancer. Cancer that has not crossed beyond the involved lobule or duct is called in situ carcinoma.

Breast Cancer (cont.) Risk factors: family history, hyperplasia, long menstrual history, obesity after menopause, oral contraceptives Treatment: lumpectomy, radical mastectomy, radiation, chemotherapy Prevention: exercise 25

Breast Self-Examination A woman’s first line of defense is self-exams, done monthly at about mid-menstral cycle. A mammogram can detect a tumor 2 to 3 years before a manual exam. Usually women older than 40 are recommended to have a mammogram every 2 years. Figure 16.5 Copyright © 2010 Pearson Education, Inc.

Colon and Rectal Cancers Third most common cancers in men and women, with over 148,810 new cases diagnosed in 2008 Risk factors: over 50 years old, obese, family history of colon or rectal cancer or polyps, diets high in fats and low in fiber, smoking, high alcohol consumption, lack of exercise Ninety percent of colorectal cancers are preventable. Treatment: radiation, surgery, and possibly chemotherapy Prevention: regular exercise, a diet heavy in fruits and plant-origin foods, a healthy weight, and moderation in alcohol consumption Colorectal cancer is the second-leading cancer killer in the United States, but it doesn't have to be. If everybody aged 50 or older had regular screening tests, as many as 90 percent of deaths from colorectal cancer could be prevented.

Skin Cancer Long-term sun exposure can result in skin cancer. Malignant melanoma is the deadliest form of skin cancer. The sun emits three types of harmful rays UVA UVB UVC Each year, about 1 million people in the United States develop skin cancer. It is almost always curable, usually with surgery alone, if found early and treated right away. It is possible to prevent some types of skin cancer. One in five Americans can expect to develop skin cancer. UVB and UVA rays are major causes of skin cancer. Tanning salons and sun lamps also increase the risk of skin cancer because they produce ultraviolet radiation.

Types of Ultraviolet Rays Copyright © 2010 Pearson Education, Inc. 29

Skin Cancer (cont.) Use the ABCD rule to detect melanoma. Asymmetry: half of a mole does not look like the other half Border irregularity: the edges are uneven Color: pigmentation is not uniform Diameter: larger than a pea Detection Watch for change in an existing mole, development of a new one, or a changing pigmented mole. Treatment Treated with electrodesiccation and topical chemotherapy; removed with lasers, chemical peels, or dermabrasion. If it is melanoma and has spread, it is a different story.

Types of Skin Cancers The most common skin cancers are basal cell (base of epidermis, top level of skin) and squamous cell (involving cells in the epidermis). Skin lesions such as actinic Kerasotes can become squamous cell carcinoma. Smoking and exposure to asphalt, coal tar, and pitch may increase risk. Basal and squamous cell carcinomas are sometimes called non-melanoma skin cancer. Melanoma is the deadliest type of skin cancer, which begins in the meloncytes. Melanoma usually occurs because of overexposure to UV rays, from sun light or tanning salons. Characteristics that increase risk include fair skin, a tendency to develop freckles, a history of childhood sunburn, a personal or family history, and a large number of moles. Copyright © 2010 Pearson Education, Inc.

ABC News Video: Possible Melanoma Treatment Discussion Questions Do scientific successes against cancer cause your worry about getting cancer to decrease? What do you do to protect yourself from skin cancer? Could you do more?

Prostate Cancer Most common cancer in American men, excluding skin cancer In 2008, 186,320 new cases were diagnosed. One in three men will be diagnosed in his lifetime. Prostate is a muscular, walnut-sized gland surrounding part of the urethra and whose primary function is to produce seminal fluid. Prostate cancer is the most common form of cancer, except for some kinds of skin cancer, among men in the United States. In fact, prostate cancer is the second-leading cause of cancer deaths among men in the United States, after lung cancer, and the seventh-leading cause of death overall for men in this country.

Prostate Cancer (cont.) Symptoms: weak or interrupted urine flow, difficulty starting or stopping urination Risk factors: age, race, nationality, family history, diet, and lifestyle Prevention: diet high in lycopenes, vitamin E 34

Ovarian Cancer Fifth-leading cause of cancer death for women; almost 22,000 new cases diagnosed and more than 15,000 deaths reported in 2008 Most common symptom is enlargement of the abdomen. Risk factors: family history, age, childbearing, cancer history, fertility drugs, talc use in genital area, genetic predisposition Prevention: diet high in vegetables and low in fat, exercise, sleep, stress management, and weight control Ovarian cancer causes more deaths than any other cancer of the female reproductive system.† But when ovarian cancer is found in its early stages, treatment is most effective.

Cervical and Endometrial (Uterine) Cancer In 2008 in the United States, there were 11,070 new cases of cervical cancer; 40,100 of endometrial cancer. In a pap test, cells are taken from the cervical region. Risk factors: For cervical cancer, early age at first intercourse, multiple sex partners, cigarette smoking, and certain STIs For endometrial cancer: age, endometrial hyperplasia, overweight, diabetes, and high blood pressure Cervical cancer is the easiest female cancer to prevent, because there is a vaccine and a screening test available. It also is highly curable when found and treated early.

Testicular Cancer Affected nearly 7,920 young men in 2007 Men between the ages of 15 and 35 are at the greatest risk. Important to practice regular testicular self-exams Lance Armstrong Foundation’s LiveStrong campaign raises awareness. Testicular cancer is the most common cancer for men age 15 to 35. As with breast cancer, early detection is the key to successful treatment. Men can increase their chances of finding testicular cancer early by performing monthly testicular self-examination (TSE).

Testicular Self-Examination Copyright © 2010 Pearson Education, Inc.

Other Cancers Pancreatic cancer has a 5-year survival rate of 5%. Leukemia is a cancer of blood-forming tissues. Lymphomas are cancers of the lymphatic system. Pancreatic cancer displays few early symptoms. Leukemia is a cancer of the blood-forming tissues that leads to proliferation of millions of immature white blood cells. Lymphomas are among the fastest-growing cancers, with nearly 75,000 new cases in 2008.

Detecting Cancer The earlier the diagnosis, the better the prospect for survival. Tests for detection Magnetic resonance imaging (MRI) Computerized axial tomography (CAT) scan Prostatic ultrasound Regular self-exams and checkups If current rates increase, about 83 million people will eventually develop cancer.

If current rates increase, about 83 million people will eventually develop cancer. Copyright © 2010 Pearson Education, Inc. 41

Cancer’s Seven Warning Signals Copyright © 2010 Pearson Education, Inc.

New Hope in Cancer Treatments Radiotherapy Chemotherapy Immunotherapy Cancer-fighting vaccines Gene therapy Angiogenesis inhibitors

ABC News Video: Treating Cancer with Bone Drugs Discussion Questions Why do treatments such as this seem to focus on early-stage cancers? Would you take a drug developed for a different health issue to help control the spread of cancer? How might taking a drug affect the rest of your body? What questions should you ask your health care provider before taking medication? Under what circumstances would you join a medical research study?

Radiation Therapy Copyright © 2010 Pearson Education, Inc.

Talking to Your Doctor about Cancer Kind of cancer? Type? Stage? Prognosis? Treatment choices? Short- and long-term effects of treatment? 46

Copyright © 2010 Pearson Education, Inc.

Cancer Survivors Cancer support groups Cancer information workshops Low-cost medical consultation Increased government funding to seek cures