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CANCER: UNDERSTANDING RISKS AND MEASURES OF PREVENTION

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Title: CANCER: UNDERSTANDING RISKS AND MEASURES OF PREVENTION


1
CANCER UNDERSTANDING RISKS AND
MEASURES OF PREVENTION
2
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

3
  • 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
4
  • Nagging cough
  • Thickening or lump
  • A sore that does not heal
  • Persistent indigestion
  • Unusual bleeding or discharge
  • Change in bowel or bladder functions

5
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

6
  • 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

7
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

8
  • 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

9
  • 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)

10
  • 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

11
  • Cancer develops over time
  • Cells of a tumor can be removed through a
    procedure called a biopsy

12
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

13
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

14
  • 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

15
  • 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

16
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

17
  • 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

18
ENVIRONMENTAL FACTORS IN CANCERTumor Viruses
  • Only four tumor viruses have been identified with
    human cancers

19
  • 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

20
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

21
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

22
  • 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

23
  • 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

24
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

25
  • 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

26
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

27
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

28
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

29
  • 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

30
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

31
  • 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

32
  • Coping with cancer requires conviction and
    courage
  • The patient must believe that a cure is possible

33
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.

BSE/TSE
34
  • 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.

35
  • 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.

36
  • 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.
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