Chapter 13 Cancer: Understanding Risks and Means of Prevention

1. Chapter 13Cancer: Understanding Risks and Means of Prevention

2. Cancer: Understanding Risks and Means of Prevention • Learning Objectives • Identify and describe the most important ways to prevent cancer. • Briefly discuss the incidence of cancer today and why mortality has not fallen. • Define the following terms: cancer, tumor, benign tumor, or, metastasis, and xenoestrogen. • Explain the difference between inherited diseases and genetic diseases.

3. Cancer: Understanding Risks and Means of Prevention • Learning Objectives (continued) • Describe the kinds of environmental agents that cause cancer. • Explain ways to prevent skin cancer. • Discuss some risk factors associated with breast cancer. • Describe how to do a breast self-exam (BSE). • Describe how cigarette smoke contributes to cancer.

4. Cancer: Understanding Risks and Means of Prevention • Learning Objectives (continued) • Discuss the association between diet and cancer. • Briefly describe the three medical treatments for cancer. • Describe several coping mechanisms for someone with cancer. • Explain the risks and benefits of being tested for cancer susceptibility gene.

5. Cancer: Understanding Risks and Means of Prevention • Understanding Cancer • Causes of Cancer • Environmental Factors that Cause Cancer • Facts About Common Cancers • Diet and Cancer Risk • Cancer Treatments

6. Question 1: The risk of dying from cancer in the United States is increasing. FALSE. The risk of dying from cancer in the United States has decreased from 1975 to 2012.

7. Question 2: Cancer can be spread from person to person. FALSE. Cancer cannot be passed from one person to another. Though cancer itself isn’t contagious, sometimes viruses, which are contagious, can lead to the development of cancer.

8. Question 3: What someone does as a young adult has little effect on their chance of getting cancer later in life. FALSE. Most cases of cancer are the consequence of many years of exposure to several risk factors.

9. Question 4: There is currently a cure for cancer but the medical industry won’t tell the public about it because they make too much money treating cancer patients. FALSE. Plenty of doctors and their loved ones die of cancer each year. Why would anyone hide such an important discovery? Think about the speed with which other medical breakthroughs in vaccines and antibiotics have been announced and applied.

10. Question 5: Treating cancer with surgery can cause it to spread throughout the body. FALSE. Specialists in cancer surgery know how to safely take biopsy samples and to remove tumors without causing the cancer to spread. In many cases, surgery is an essential part of the cancer treatment plan.

11. Question 6: Cancer can be effectively treated. TRUE. The five major types of treatment for cancer are surgery, radiation, chemotherapy, biologic therapies, and therapies that boost the patient’s immune system.

12. Question 7: Cancer is a group of over 100 diseases. TRUE. • The main categories of cancer include: • Carcinoma • Sarcoma • Leukemia • Lymphoma and myeloma • Central nervous system cancers

13. Question 8: Cancer cells can be distinguished from normal cells because of their abnormal growth. TRUE. Normally, cells grow and divide to produce more cells as they are needed to keep the body healthy. Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should.

14. Question 9: Cancer can only occur in specific cells in the body. FALSE. The body is made up of many types of cells, and all cancer begins in cells. Cancer can develop in any cell in the body, which is why there are so many different types.

15. Question 10: Cancer develops because of abnormal gene function. TRUE. Scientists have learned that cancer is caused by changes in genes that normally control the growth and death of cells. Certain lifestyle and environmental factors can change some normal genes into genes that allow the growth of cancer.

16. Cancer: Understanding Risks and Means of Prevention • 1 in 2 men and 1 in 3 women will develop some form of cancer in their lifetimes. • Each year nearly 600,000 Americans die from cancer. • Half of all cancer cases can be cured if detected early.

17. Cancer: Understanding Risks and Means of Prevention • Most cancers are preventable with a healthy lifestyle. • Avoid cigarette smoke and tobacco in any form. • Maintain a healthy weight and be physically active. • Maintain good nutrition.

18. Get ScreenedEarly Diagnosis=Probable Cure

19. Understanding Cancer • “Cancer” is from the Latin word meaning crab. • Cancer is unregulated multiplication of specific cells in the body. • A tumor develops when a normal body cell grows abnormally and reproduces too rapidly. • Benign tumors do not spread to other parts of the body. • Malignant tumors are composed of cells that multiply rapidly, have abnormal properties, and invade other normal tissue.

20. Understanding Cancer • The cells of most malignant tumors undergo metastasis, a process where the cells detach from the original tumor, enter the lymphatic system and bloodstream, and are carried to other organs. • Watch Understanding Cancer 5 min

21. Understanding Cancer • Cancers are medically classified according to the organ or tissue in which the tumor originates. • Carcinomasbegin in the skin or tissues that line the internal organs (most common type) • Sarcomas develop in the bone, cartilage, fat, muscle or other connective tissues. • Leukemias begin in blood and bone marrow • Lymphomas start in the immune system • Central nervous system cancers develop in the brain and spinal cord.

23. Understanding Cancer • Fifty percent of all human cancers originate in one of four organs: • Lungs • Breast • Prostate • Colon • Biopsy—once a tumor is detected, cells can be removed from it using this procedure

24. Understanding Cancer • Stages of Cancer • Stage I: Cancer cells can be distinguished from normal cells. • Stage II: Cancer cells begin to metastasize and may migrate to nearby lymph nodes. • Stage III: Cancer cells have spread throughout the body and tumors may have started to grow in other organs. • Stage IV: Often a terminal stage; tumors are found throughout the body and usually are resistant to treatment. Watch Breast C staging 2min

25. Understanding Cancer Number of Deaths

26. Causes of Cancer • 90–95% of all cancers are not inherited from parents. • A persistent fear of developing cancer can generate stress that may weaken the immune system and contribute to the development of disease, including cancer. • Genes can be altered by environmental agents, which transform cells into cancer cells. Cancer is a genetic disease but not an inherited disease.

27. Causes of Cancer • Studies on identical twins show that most of the time cancer is not an inherited disease. • Cancer Susceptibility Genes • Are extremely rare, 5% to 10% of all cancers. • Makes a person more vulnerable to environmental factors that contribute to the risk of developing cancer. • Being identified as a carrier does not guarantee that you will have cancer

29. Causes of Cancer Cancer Development

30. Environmental Factors That Cause Cancer • It is difficult to pinpoint a single cause of cancer, but certain environmental factors are strongly associated with the occurrence of particular cancers. • Epidemiological studies show that 80% to 90% of cancers are caused by exposure to environmental factors known to increase the risk of cancer. • For example, smoking cigarettes = 10–20 times higher risk later in life.

31. Environmental Factors That Cause Cancer

32. Environmental Factors That Cause Cancer • Three Classes of Environmental Agents • Ionizing radiation • Infectious microorganisms • Cancer-causing chemicals (chemical carcinogens)

33. Environmental Factors That Cause Cancer

34. Environmental Factors That Cause Cancer • Three Classes of Environmental Agents Ionizing Radiation • X-rays, UV light, radioactivity whose energy can damage cells and chromosomes • UV Light—UVA and UVB wavelengths are both dangerous

35. Environmental Factors That Cause Cancer • Three Classes of Environmental Agents (continued) • Infectious Microorganisms • “Tumor viruses”—only a few viruses have been associated with human cancers; in most people, these viruses will not cause cancer. • Hepatitis B and C (liver cancer) • Papillomavirus (genital and cervical cancers) • Human T cell leukemia-lymphoma virus (leukemia and lymphoma) • Epstein-Barr virus (cancer of the nose or pharynx) • HIV (Kaposi’s sarcoma) • H. pylori (gastric cancer, lymphoma, and possibly pancreatic cancer)

36. Environmental Factors That Cause Cancer • Three Classes of Environmental Agents Chemical Carcinogens • Environmental chemicals that can interact with cells to initiate cancer: • Tobacco • Pesticides • Asbestos • Heavy metals • Benzene • Nitrosamines

37. Environmental Factors That Cause Cancer

38. Environmental Factors That Cause Cancer • Three Classes of Environmental Agents Chemical Carcinogens • Mesothelioma: a rare form of lung cancer that only occurs among persons exposed to asbestos fibers. • Industry exposure risk is low compared to tobacco and diet.

39. Environmental Factors That Cause Cancer • Do Xenoestrogens Cause Cancer? • Xenoestrogensare chemicals found in the environment that mimic estrogen and aid in the development of cancer, specifically breast cancer. • Substances that contain xenoestrogens: • DDT • Pesticides • Polychlorinated biphenyls (PCBs) • Bisphenol-A (BPA) • Gasoline vapor

40. Environmental Factors That Cause Cancer • Do Xenoestrogens Cause Cancer? Eating broccoli, cabbage, and soy products may help counteract the effects of xenoestrogens.

41. Facts About Common Cancers • Lung Cancer • Lung cancer causes more deaths among men and women than any other form of cancer does. • Accounts for 15% of all cancers. • Lung cancer could be almost completely prevented if people would stop (or never start) smoking. • Main cause of nearly 90% of lung cancers. • Lung cancer rate is increasing in other nations.

42. Facts About Common Cancers • Breast Cancer • Both men and women can develop breast cancer, but it occurs very rarely among men. • Factors that have been proposed as contributing to the increased rate of breast cancer include: • Increased weight • Less exercise • Increased dietary fat

43. Facts About Common Cancers • Breast Cancer (continued) • Other factors that increase risk: • Having a mother who had breast cancer before age 60. • Experiencing menarche before age 14. • Having your first child after age 30 or having no biological children. • Experiencing menopause after age 55. • Having benign breast disease.

44. Facts About Common Cancers • Breast Cancer (continued) • Other factors that increase risk: • (HRT) Having estrogen replacement therapy after age 55. • Consuming more than 3 ounces of alcohol per day. • Having inherited BRCA1 or BRCA2 genes.

45. Facts About Common Cancers • Breast Cancer (continued) • Ways to prevent and detect breast cancer: • 10% of women in industrialized countries will get breast cancer. • Living healthfully—maintaining normal body weight, low-fat diet, consuming adequate fresh fruits and vegetables, engaging in physical activity, and limiting alcohol consumption.

46. Facts About Common Cancers • Breast Cancer (continued) • Ways to prevent and detect breast cancer: • Monthly breast self-exams beginning at age 20. • Mammograms every 1 to 2 years for women in their 40s. • The drug tamoxifen can be used for breast cancer treatment as well as for protection.

47. Facts About Common Cancers • Testicular Cancer • Rate had been increasing in young men, possibly because of exposure to xenoestrogens. • Fairly rare and can be cured if detected early.

48. Facts About Common Cancers • Prostate Cancer • Prostate cancer occurs mostly in men over age 65. • Early diagnosis relies on two tests: • Finger rectal exam • Prostate-specific antigen test (PSA) • Detects a protein in blood that is associated with abnormal growth of the prostate gland. • This cancer develops very slowly. • The U.S. Preventive Services Task Force recommends against any routine screening for prostate cancer.

49. Facts About Common Cancers • Skin Cancer • Melanoma is a malignant form of skin cancer. • It is the fifth most frequently diagnosed cancer among Americans. • Exposure to sunlight is the primary cause of all forms of skin cancer.

50. Facts About Common Cancers • Skin Cancer (continued) • Most common cancer in women ages 25–29 and the second most common in women ages 30–34. • Having dark skin makes a person 500 times less likely to get melanoma.