CANCER: UNDERSTANDING RISKS AND MEASURES OF PREVENTION

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CANCER UNDERSTANDING RISKS AND
MEASURES OF PREVENTION
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INTRODUCTION

• About 2 out of every 5 Americans will develop
  some type of cancer during their lifetime about
  1 in 5 will die from cancer (40 and 20,
  respectively)
• Most cancers are preventable
• Cigarette smoke is estimated to cause about 30
  of all forms of cancer
• A healthy diet reduces the risk of cancer

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• About 50 of cancer patients can be cured if
  their cancer is detected at an early stage
• Cured means a persons life expectancy is the
  same as a person who never had cancer
• The American Cancer Society recommends watching
  for certain warning signs that indicate cancer
  may be developing
• Change in a wart or mole
• Hoarseness (persistent)
• Difficulty in swallowing

American Cancer Society
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• Nagging cough
• Thickening or lump
• A sore that does not heal
• Persistent indigestion
• Unusual bleeding or discharge
• Change in bowel or bladder functions

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UNDERSTANDING CANCERIncidence of Various Cancers

• Certain cancers in the U.S. have remained steady
  over the past 50 years for both men and women
  (esophagus, bladder, pancreas)
• Stomach cancer has declined in both sexes liver,
  uterine, and colon cancers have declined in women

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• Unfortunately there has been an increase in lung
  cancer among both men and women
• The major reason is cigarette smoking
• In addition to lung cancer, increases are seen
  in breast, prostate, and skin cancers

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UNDERSTANDING CANCERWhat is Cancer?

• The term cancer comes from the Latin word meaning
  crab cancer is now defined as the unregulated
  growth of specific cells in the body
• Refers to over 100 different diseases
• If a normal cell begins to grow abnormally and
  reproduces too rapidly, a mass of abnormal cells
  eventually develops a tumor

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• If cells remain localized at the site of origin
  and if the cells multiply slowly, the tumor is
  referred to as a benign tumor
• Cysts, warts, moles
• Usually removed surgically and generally not a
  threat to life
• Benign tumors can regrow
• Malignant tumors are composed of cells that grow
  rapidly, have abnormal properties, and invade
  other normal cells
• Malignant cells have altered shapes

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• A pathologist (specializes in the causes of
  diseases) can determine whether the cells removed
  from a tumor are abnormal and to what degree
• The cells of most malignant tumors undergo
  metastasis (a process where cells detach from
  the original tumor, enter the lymphatic system
  and bloodstream, and are carried to other
  organs)

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• Cancers are medically classified according to the
  organ or tissue in which the tumor originates
• Four major categories
• Carcinomas (epithelial tissues, skin, nerves,
  breasts, etc..)
• Sarcomas (connective tissues, bone, muscles, fat,
  and blood vessels)
• Leukemias (organs and tissues that form blood
  cells)
• Lymphomas (similar to leukemias)
• About one-half of all human cancers originate in
  one of four organs lungs, breast, prostate or
  colon

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• Cancer develops over time
• Cells of a tumor can be removed through a
  procedure called a biopsy

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UNDERSTANDING CANCERMost Cancers are Not
Inherited

• Most scientific research indicates that 90 to 95
  of all cancers (including breast, lung, stomach,
  colon, skin or prostate cancers) are not
  inherited from parents (except in a few families)
• Genetic refers to genes that are changed in a
  persons body cells inherited means that
  defective genes were passed on

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ENVIRONMENTAL FACTORS IN CANCER

• The risk factors associated with cancer are
  complex
• It is difficult to pinpoint a single cause of
  cancer, but certain environmental factors are
  strongly associated with the occurrence of
  particular cancers
• Cigarette smoking and lung cancer
• Exposure to ultraviolet light and skin cancer

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• Epidemiology is the branch of science that
  investigates the causes and frequencies of
  diseases in human populations
• Epidemiological studies show that 80 to 90 of
  cancers are caused by exposure to environmental
  factors known to increase the risk of cancer

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• There are 3 classes of environmental agents
• Ionizing radiation
• Tumor viruses
• Chemical carcinogens
• Each of these agents increases the risk of cancer
  by producing chemical agents in genes called
  mutations

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ENVIRONMENTAL FACTORS IN CANCERIonizing
Radiation

• Ionizing radiation consists of X-rays, UV light,
  and radioactivity whose energy damages cells and
  chromosomes
• Because any amount of ionizing radiation, however
  small, has potential for causing damage one
  should minimize exposure to X-rays

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• The most common source of radiation is the
  ultraviolet (UV) radiation in sunlight
• The rate of skin cancers have increased over the
  years
• Melanoma - is a dangerous form of skin cancer
• The most common skin cancer is squamous cell
  carcinoma
• UV radiation has two different wavelengths
• UVA and UVB - both are harmful

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ENVIRONMENTAL FACTORS IN CANCERTumor Viruses

• Only four tumor viruses have been identified with
  human cancers

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• Increased cancer risk due to viruses occur with
  liver cancer (hepatitis B), genital cancer
  (papilloma virus), leukemia and lymphoma (human
  T-cell leukemia-lymphoma virus), and cancer of
  the nose in Africans (Epstein-Barr virus)
• The causes for most cancers are in environmental
  factors rather than tumor viruses

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ENVIRONMENTAL FACTORS IN CANCERChemical
Carcinogens

• A chemical carcinogen is an environmental
  chemical that can interact with cells to initiate
  cancer (usually by altering the chromosomes or
  genes in the cells)
• Many substances have been tested for carcinogenic
  elements but many have not
• Those we know of and should avoid include
  cigarette smoke, pesticides, asbestos, heavy
  metals, benzene and nitrosamines

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REDUCING CANCER RISK Reducing Risk of
BreastCancer

• There is a significant association between the
  rate of breast cancer and the amount of fat in
  the diet of people in various countries
• Other risk factors associated with breast cancer
  include high radiation exposure, late
  child-bearing, late menopause, and high
  lifetime exposure to estrogen

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• Early detection is the key
• Regular breast self-examinations
• The American Cancer Society recommends a
  screening mammogram by age 40

• Women 40-49 should get a mammogram every 1-2
  years
• Women over 50 should get a mammogram every year
• The amount of X-rays in the mammogram are very
  low, and outweigh the possible risk of not
  detecting breast cancer early

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• Men also get breast cancer, but the incidence is
  low
• Xenoestrogens, which mimic the natural effects of
  estrogen in women, maybe one reason for the
  increase in breast cancer due to exposure to
  them

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REDUCING CANCER RISKReducing Risk of
Testicular and Prostate Cancer

• The rates of testicular and prostate cancer have
  been increasing, and like breast cancer the
  causes are unknown for the most part
• Testicular cancer is rare but can occur in young
  men, which is why a testicular self-examination
  is important for early detection

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• Prostate cancer generally occurs in men over 65
  year of age
• Early diagnosis is facilitated by two tests

• Finger rectal exam by a physician, who can
  feel the prostate and determined if
  enlarged
• Prostate-specific antigen (PSA) which detects a
  protein in the blood associated with abnormal
  growth of the prostate gland

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REDUCING CANCER RISKRegulating Diet

• Many studies show that diet is associated with
  cancer
• Certain dietary choices may help prevent cancer
  most of these help boost the immune system

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CONFRONTING CANCERCancer-Susceptibility Genes

• Only about 5 to 10 of all cancers are due to
  heredity
• Some people inherit cancer-susceptibility genes
• A cancer-susceptibility gene makes a person more
  vulnerable to environmental factors that increase
  risk of cancer
• Identification of cancer-susceptibility genes in
  people raises ethical issues

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CONFRONTING CANCERSeeking Cancer Treatments

• There are three medical treatments for cancer
• Surgery - surgical removal of all or most of the
  tumor
• Radiation therapy - X-rays or other forms of high
  energy radiation used to destroy cancer cells
• Chemotherapy - use of toxic chemicals to kills
  cancer cells

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• Cancer treatments today are not noticeably more
  successful than in the past although there have
  been successes with childhood leukemia,
  testicular cancer, and Hodgkins disease

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CONFRONTING CANCERCoping with a Diagnosis of
Cancer

• A diagnosis of cancer can raise serious problems
  for the patient, and family and friends
• Coping can be difficult
• Denial on patients part, or familys part
• Patient must have surgery or other treatment
• Patient and family must face death

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• Stress and emotional upset can depress the immune
  system
• Mental relaxation techniques and focusing on
  images and suggestions can help the immune system
  fight and destroy cancer cells
• The coping strategies for dealing with the
  emotional distress of many chronic, fatal
  illnesses are similar

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• Coping with cancer requires conviction and
  courage
• The patient must believe that a cure is possible

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HEALTH IN REVIEW

• Cancer refers to a number of different diseases,
  all of which share the common property of
  abnormal, unregulated cell growth in the body.
• Both breast and testicular self-examinations are
  positive means of early cancer detection.
• The principal environmental agents that cause
  cancer are ionizing radiation, tumor viruses, and
  carcinogenic chemicals.

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• If everything known about cancer prevention were
  practiced, up to two-thirds of cancers would not
  occur thus cancer is largely a preventable
  disease.
• Only 5 to 10 percent of cancers are caused by
  genes that have been inherited. The genetic
  changes in body cells that result in cancer are
  not passed on to children, as these genetic
  changes have not occurred in sperm or eggs.

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• The treatments for cancer include surgery,
  radiation, and chemotherapy which are designed to
  destroy as many cancer cells as possible.
• Recovery from cancer depends on good nutrition,
  positive attitudes, healing images, and medical
  treatment appropriate for the particular cancer.
  A healthy, active immune system also is an
  essential component in cancer prevention and
  recovery.

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• Cigarette smoking is responsible for about
  one-third of all cancers and dietary deficiencies
  or excesses for about one-half.
• Overexposure to sunlight causes skin cancer,
  which is increasing.
• Significantly reducing cancer requires major
  changes in peoples life-styles, including more
  attention to a healthy diet, elimination of
  tobacco use, limiting alcohol consumption, and
  reducing exposures to intense sunlight and
  chemical carcinogens.