Transcript Cancer

CHAPTER
OUTLINE
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Chapter 12
Cancer
Prevention
Cancer
Development
Incidence of
Cancer
Key Terms
Cancer: Group of diseases
characterized by
uncontrolled growth and
spread of abnormal cells
Benign: Noncancerous
Malignant: Cancerous
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer
Development
Incidence of
Cancer
Key Terms
Deoxyribonucleic acid
(DNA): Genetic substance of
which genes are made;
molecule that contains cell’s
genetic code
Ribonucleic acid (RNA):
Genetic material that guides
the formation of cell proteins
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Key Terms
Oncogenes: Genes
that initiate cell division
Suppressor genes:
Genes that deactivate
the process of cell
division
Angiogenesis:
Formation of blood
capillaries
Metastasis: The
movement of cells from
one part of the body to
another
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer Development
More than 100 types of cancer can develop in the body
The process of cancer begins with an alteration in DNA
Within DNA are oncogenes and tumor suppressor genes, which
normally work together to repair and replace cells
Defects in these genes ultimately allow the cell to grow into a
tumor; defects are caused by
External factors such as radiation, chemicals, and viruses
Internal factors such as immune conditions, hormones,
and genetic mutations
Cancer starts with the abnormal growth of one cell,
which then can multiply into billions of cancerous cells
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer Development
A critical turning point in the development of cancer is
when a tumor reaches about one million cells
At this stage, it is referred to as carcinoma in situ
An undetected tumor may go for months or years
without any significant growth
While encapsulated, it does not pose a serious threat
to human health
To grow, tumors require more oxygen and nutrients
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer Development
In time, a few cancer cells start producing chemicals
that enhance angiogenesis (capillary or blood vessel
formation into the tumor)
Angiogenesis is the precursor of metastasis
Through the new blood vessels formed by
angiogenesis:
Cancerous cells break away from a malignant tumor
They migrate to other parts of the body
They can cause new cancers
12.4
How Cancer Starts and Spreads
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer Development
Once cancer cells metastasize, treatment
becomes more difficult
Therapy can kill most cancer cells, but a few
cells might become resistant to treatment
Treatment-resistant cells can grow into a new
tumor that will not respond to the same
treatment
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer Statistics
Cancer is the second leading cause of death
in the U.S.
About 23% of all yearly deaths are caused
by cancer
Aproximately 1 in 2 men and 1 in 3 women
in the U.S. will develop cancer
More than 560,000 Americans die from
cancer each year
More than 1.3 million new cases are
diagnosed each year
Death Rates for Major Cancer Sites
12.5
Death Rates for Major Cancer Sites
12.5
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Critical Thinking
Have you ever had or do you now
have any family members with
cancer?
Can you identify lifestyle or
environmental factors as possible
contributors to the disease?
If not, are you concerned about your
genetic predisposition, and are you
making lifestyle changes to
decrease your risk?
Warning
Signals of
Cancer
Recommended
Checkups
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer-Causing Factors
As much as 80% of all human cancer is
related to lifestyle or environmental factors
Diet
Obesity
Tobacco use
Sedentary lifestyle
Excessive use of alcohol
Exposure to occupational hazards
Cancer-Causing Factors
SOURCE: Harvard Center for Cancer Prevention. Causes of Human Cancer, Harvard
Report on Cancer Prevention, 1 (1996).
12.7
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Guidelines for
Preventing Cancer
Get proper nutrition
Abstain from tobacco
Avoid excessive sun exposure
Monitor estrogen, radiation exposure, and
potential occupational hazards
Engage in physical activity
Maintain recommended body weight
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Dietary Guidelines
Predominately a vegetarian diet (high in fiber and low in fat)
Should include a variety of fruits and vegetables, in particular
cruciferous vegetables
The use of tea, soy products, calcium, and omega-3 fats is
encouraged
Adequate fiber intake is recommended (25 to 38 gr/day)
Protein intake should be kept within the recommended
guidelines
Avoid salt-cured, smoked, and nitrite-cured foods (nitrite and
nitrates are used to prevent the growth of harmful bacteria in
processed meats but lead to the formation of nitrosamines, which
cause stomach and esophageal cancers)
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Dietary Guidelines
Alcohol, if used at all, should be consumed in
moderation, 1 (women) to 2 (men) servings per day
Grilling of meats at high temperatures is discouraged
Consume ample amounts of fruits and vegetables
which are high in antioxidants and phytochemicals
Antioxidants seem to
Absorb free radicals before they can cause damage
Interrupt the sequence of reactions once damage has begun
Phytochemicals (plant chemicals) seem to prevent cancer by
blocking the formation of cancerous tumors and disrupting
the process at almost every step of the way
Lowering Cancer Risks
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Abstain from Tobacco Use
The biggest carcinogenic exposure in the
workplace is cigarette smoke
Of all cancers, at least 30% are tied to
smoking, and 87% of lung cancers are linked
to smoking
Use of smokeless tobacco increases the risk
for mouth, larynx, throat, and esophageal
cancers
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Avoiding Excessive Sun
Excessive exposure to ultraviolet radiation (both UVB and UVA
rays) contributes to skin cancer
1 in every 6 Americans will develop some type of skin cancer
The most common sites of skin cancer are those areas exposed
to the sun most often (face, neck, and back of the hands)
Nearly 90% of the almost 1 million yearly cases of basal cell or
squamous cell skin cancers in the U.S. could be prevented by
protecting the skin from the sun
Melanoma is the most deadly form of skin cancer, causing 7,600
yearly deaths
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Avoiding Excessive Sun
Tanning of the skin is the body’s natural reaction to permanent
damage from too much sun
Even small doses of sunlight add up to a greater risk for skin
cancer and premature aging
Avoid sun exposure between 10:00 am and 4:00 pm
Sun lamps and tanning parlors provide mainly ultraviolet A rays
(UVA) and have been linked to melanoma
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Avoiding Excessive Sun
Apply sunscreen lotion about 30 minutes before lengthy
exposure to the sun
A sun protection factor (SPF) of at least 15 is recommended
When swimming or sweating, reapply waterproof sunscreens
often (sunscreens lose strength when diluted)
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Critical Thinking
What significance does a “healthy tan”
have in your social life?
Are you a “sun-worshiper,” or are you
concerned about skin damage,
premature aging, and potential skin
cancer in your future?
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Monitoring Estrogen, Radiation Exposure,
& Potential Occupational Hazards
Use of estrogen therapy has been linked to endometrial cancer
in some studies
Exposure to radiation increases the risk for cancer
(use the lowest dose possible to keep cancer risk down)
Occupational hazards increase the risk for cancer
Examples include asbestos fibers, nickel and uranium dusts,
chromium compounds, vinyl chloride, and bischlormethyl ether
Cigarette smoking magnifies the risk from
occupational hazards
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Maintain Physical Activity
An active lifestyle seems to have a protective
effect against cancer
Cancer mortality in active men and
women is lower
A daily 30-minute moderate-intensity exercise
program lowers the risk for colon cancer and
may lower the risk for cancers of the breast
and reproductive system
Association between Physical Fitness
and Cancer Mortality
11.9
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Cancer Promoters
Physical inactivity
Being more than 10 pounds overweight
Frequent consumption of red meat
A diet high in fat
Charred/burned foods
Frequent consumption of nitrate/nitrite-cured,
salt-cured, or smoked foods
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Cancer Promoters
Alcohol consumption
Excessive sun exposure
Estrogens
Methyleugenol (flavoring agent in
packaged foods)
Radon
Wood dust (high levels)
Recommended
Checkups
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Warning Signals of Cancer
Change in bowel or bladder habits
Sore that does not heal
Unusual bleeding or discharge
Thickening or lump in breast or elsewhere
Indigestion or difficulty in swallowing
Obvious change in wart or mole
Nagging cough or hoarseness
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Recommended Checkups
Include health counseling
Depending on age and gender, may include
examinations for
cancers of the thyroid, oral cavity, skin, lymph nodes,
testes, and ovaries
some nonmalignant diseases
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Recommended Checkups
Breast checkup
Women 40 and older should
Have an annual mammogram
Have an annual clinical breast examination (CBE)
Optional breast self-examination (BSE)
Women 20–39 should
Have a clinical breast examination every 3 years
Optional BSE
Women at increased risk (family or personal
history) should discuss frequency and additional
testing with their doctors
Cancer
Development
Incidence of
Cancer
Guidelines for
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Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Recommended Checkups
Colon & rectum checkup
Beginning at age 50 follow one of the
examination schedules below:
Fecal occult blood test (FOBT) or fecal
immunochemical test (FIT) every year
Flexible sigmoidoscopy (FSIG) every 5 years
FOBT or FIT every year and FSIG every 5 years
Double-contrast barium enema every 5 years
Colonoscopy every 10 years
Cancer
Development
Incidence of
Cancer
Guidelines for
Preventing
Cancer
Warning
Signals of
Cancer
Recommended
Checkups
Recommended Checkups
Prostate checkup
Beginning at age 50, men with life expectancy of at
least 10 years should have the choice of having
these tests annually
A prostate-specific antigen (PSA) test
A digital rectal exam
Men at high risk (African-American and strong
family history) should begin testing at age 45
Cancer
Development
Incidence of
Cancer
Guidelines for
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Cancer
Warning
Signals of
Cancer
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Recommended Checkups
Uterus checkup
Cervix: Three years after beginning of vaginal
intercourse, but no later than 21, women should have a
Pap test each year or a liquid-based test (less frequent
after the age of 30 and following three consecutive tests
with normal findings)
Endometrium:
At menopause all women should be informed about risks and
symptoms and report unexpected bleeding or spotting to their
doctors
Beginning at age 35, women with or at risk for hereditary
nonpolyposis colon cancer should be offered an endometrial
biopsy annually
End of Chapter