Download Cancer

Chapter
12
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1

Ahead:
 What Is Cancer?
 The Causes of Cancer
 Common Cancers
 Detecting and Treating Cancer
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2

Cancer: abnormal, uncontrolled multiplication
of cells, which, if left untreated, can ultimately
cause death
 Cancer is responsible for 1 out of every 4 deaths in
the U.S. each year, and it is the second leading
cause of death after heart disease
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3

Tumor: a mass of tissue that serves no
physiological purpose; also called a neoplasm
 Benign tumor: a tumor that is not cancerous
 Malignant tumor: a tumor that is cancerous and
capable of spreading
 Lymphatic system: a system of vessels that
returns proteins, lipids, and other substances from
fluid in the tissues to the circulatory system
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4

Cancer begins when a malignant cell divides
without regard for normal control mechanisms
 Produces a mass of abnormal cells
 Eventually detected

A few cancers, like leukemia, do not produce a
mass
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5
Metastasis: spread of cancer cells from one
part of the body to another
 Occurs because cancer cells do not stick to
each other as strongly as normal cells do and
therefore may not remain at the original site
 To control the cancer, every cancerous cell
must be removed

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6
Genetic factors
 Environmental factors
 Lifestyle factors

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7

DNA basics
 Chromosomes: threadlike bodies in a cell nucleus
that contain molecules of DNA; most human cells
contain 23 pairs of chromosomes
 DNA: deoxyribonucleic acid, a chemical substance
that carries genetic information
 Gene: a section of a chromosome that contains the
instructions for making a particular protein; the basic
unit of heredity
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8

DNA mutations and cancer
 Mutation is any change in the makeup of a gene
▪ Some mutations are inherited
▪ Others are caused by environmental agents
 Oncogene: a gene involved in the transformation of
a normal cell into a cancer cell

Cancer promoters
 Some substances accelerate the growth of cells,
which means less time for a cell to repair DNA
damage caused by other factors
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9

Smoking is responsible for up to 90% of lung
cancers and for about 29% of all cancer deaths
 Responsible for nearly one in five American deaths
each year
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10
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11

Dietary fat and meat
 Diets high in fats and meat may contribute to colon,
prostate, and stomach cancer
 Omega-6 polyunsaturated fats are associated with
a higher risk of certain cancers

Alcohol
 Associated with several cancers
 Alcohol and tobacco interact as risk factors for oral
cancer
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12

Foods cooked at high temperatures
 High levels of acrylamide, a probable human
carcinogen, found in starch-based foods that are
fried or baked at high temperatures
▪ Acrylamide is also found in tobacco

Fiber
 Experts recommend a
high-fiber diet for its
overall positive effect
on health
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13

Fruits and vegetables
 Researchers have identified mechanisms by which
food components may act against cancer
 Carotenoid: yellow-to-red plant pigments that can
be converted to vitamin A by the liver
▪ Many act as antioxidants or have other anti-cancer effects
 Phytochemical: naturally occurring substance
found in plant foods that may help prevent chronic
diseases such as cancer and heart disease
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15
FOOD
PHYTOCHEMICAL
POTENTIAL ANTICANCER EFFECTS
Chili peppers (Note: Hotter peppers contain more
capsaicin.)
Capsaicin
Neutralizes effect of nitrosamines; may block carcinogens in
cigarette smoke from acting on cells
Oranges, lemons, limes, onions, apples, berries,
eggplant
Flavonoids
Act as antioxidants; block access of carcinogens to cells;
suppress malignant changes in cells; prevent cancer cells
from multiplying
Citrus fruits, cherries
Monoterpenes
Help detoxify carcinogens; inhibit spread of cancer cells
Cruciferous vegetables (broccoli, cabbage, bok
choy, cauliflower, kale, brussels sprouts,
collards)
Isothiocyanates
Boost production of cancer-fighting enzymes; suppress
growth; block effects of estrogen on cell growth
Garlic, onions, leeks, shallots, chives
Allyl sulfides
Increase levels of enzymes that break down potential
carcinogens; boost activity of cancer-fighting immune
cells
Grapes, red wine, peanuts
Resveratrol
Act as antioxidants; suppress tumor growth
Green, oolong, and black teas (Note: Drinking
burning hot tea may increase cancer risk.)
Polyphenols
Increase antioxidant activity; prevent cancer cells from
multiplying; help speed excretion of carcinogens from the
body
Orange, deep yellow, red, pink, and dark green
vegetables; some fruits
Carotenoids
Act as antioxidants; reduce levels of cancer-promoting
enzymes; inhibit spread of cancer cells
Soy foods, whole grains, flax seeds, nuts
Phytoestrogens
Block effects of estrogen on cell growth; lower blood levels of
estrogen
Whole grains, legumes
Phytic acid
Bind iron, which may prevent it from creating cell-damaging
free radicals
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16
The ACS recommends maintaining a healthy
weight throughout life by balancing caloric
intake with physical activity
 The ACS also recommends achieving
and maintaining a healthy weight if you are
currently overweight
or obese

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18

Ingested chemicals
 Some food additives are potentially dangerous,
including the nitrates and nitrites found in processed
meats

Environmental and industrial pollution
 Less than 2% of cancer deaths are caused by
general environmental pollution
 Exposure to carcinogenic materials in the workplace
is a more serious problem
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19

Radiation
 All sources of radiation are potentially carcinogenic
 Successful efforts have been made to reduce
radiation needed for necessary medical X-rays

Microbes
 About 15–20% of the world’s cancers are caused
by microbes
▪ HPV
▪ Epstein-Barr virus
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21









Lung cancer
Colon and rectal cancer
Breast cancer
Prostate cancer
Cancers of the female reproductive tract
Skin cancer
Head and neck cancers
Testicular cancer
Other cancers
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22

Lung cancer is the most common cause of
cancer death in the U.S.
 Responsible for about 158,000
deaths a year
 When combined with other
carcinogens, risk for smokers
can increase 10 times or more
▪ Carcinogen: any substance that
causes cancer
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23

Symptoms include persistent cough, chest
pain, or recurring bronchitis
 Most often treated with a combination of surgery,
radiation, and chemotherapy
 Chemotherapy: the treatment of cancer with
chemicals that destroy cancerous cells
 Only 15% of lung cancer patients are alive 5 years
after diagnosis
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24

90% of cases are diagnosed in people
age 50 and older
 Many cancers arise from preexisting polyps
 Many cases of colon cancers may be due to
inherited gene mutations
 Protective lifestyles can affect colon cancer risk,
including good nutrition, physical activity, and not
smoking
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
Symptoms include changes in bowel habits
and bleeding from the rectum
 Tests can detect small amounts of blood in the stool
 Rectal exams can detect some tumors, as can a
colonoscopy
 Exams should be performed yearly after age 50
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27

Breast cancer is the
most common cancer
in women and is
second to lung cancer
in the number of
cancer deaths
among women
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28

Risk factors
 Strong genetic factor
 Other risk factors:
▪
▪
▪
▪
▪
▪
Early first menstruation, or late-onset menopause
Having no children or having a first child after age 30
Hormone replacement therapy
Being obese
Using alcohol
Smoking
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29

Risk factors
 The female hormone estrogen may be a
common element in some risk factors
▪ Estrogen promotes cell growth in responsive tissues, so
increased estrogen exposure may raise the risk of breast
cancer
▪ Fat cells produce estrogen, and estrogen levels are higher
in obese women
▪ Alcohol increases estrogen in the blood
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
Prevention
 Eat a low-fat, vegetable-rich diet
 Exercise regularly
 Limit alcohol intake
 Maintain a healthy body weight
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
Detection
 Mammogram: low-dose X-ray of the breasts;
used for early detection of breast cancer
 Clinical breast exam
 Breast self-exams
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
Detection
 Biopsy: removal and examination of small piece of
body tissue for purpose of diagnosis
 Ultrasonography: an imaging method in which
inaudible high-pitched sound (ultrasound) is
bounced off body structures to create an image on
a monitor
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
Treatment
 Lumps can be scanned by ultrasonography and
biopsied to check for malignancy
▪ If a lump is cancerous, several surgical treatments may
be used
▪ Chemotherapy or radiation treatment also used
 Several drugs have been developed for preventing
and treating breast cancer
 If discovered early, patients have about a
98% chance of surviving more than 5 years
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34

Prostate cancer is the most common cancer in
men and the second leading cause of cancer
death in men
 Age is the strongest predictor, with 97% of cases
occurring in men over age 50
 Prostate-specific antigen (PSA) blood test:
diagnostic test for prostate cancer that measures
blood levels of PSA
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35

Treatment is usually removal of the prostate,
but radiation may be used
 Small slow-growing tumors in older men may be
treated with watchful waiting
 5-year survival rate is now nearly 100%
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36

Cervical cancer
 Most cases stem from infection by HPV
 Pap test: scraping of cells from the cervix for
examination to detect cancer
▪ Abnormal cells are removed surgically or by destroying
them with an ultra-cold probe or localized laser treatment
 Two HPV vaccines have been approved by the FDA
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37

Uterine or endometrial cancer
 Cancer of the lining of the uterus most often occurs
after age 55
 Usually detectable by pelvic examination
 Uterine cancer is treated surgically, as well as by
radiation, hormones, and chemotherapy
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38

Ovarian cancer
 Ovarian cancer is rare compared with uterine
cancer, but it causes more deaths
▪ Often diagnosed late in its development
 Lowering woman’s lifetime number of ovulation
cycles reduces risk
▪ Symptoms: bloating, pelvic or abdominal pain, difficulty
eating or feeling full quickly, urinary problems
▪ Treated by surgical removal of ovaries, fallopian tubes,
and uterus
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39

Skin cancer is the most common cancer
 Linked to exposure to UV radiation from the sun
 Melanoma: a malignant tumor of the skin that arises
from pigmented cells, usually a mole
 Ultraviolet (UV) radiation: light rays of a specific
wavelength, emitted by the sun; most UV rays are
blocked by the ozone layer in the upper atmosphere
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
Basal cell carcinomas and squamous
cell carcinomas are 95% of skin cancers
 Basal cell carcinoma:
cancer of the deepest
layers of the skin
 Squamous cell
carcinoma: cancer
of the surface layers
of the skin
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
Melanoma is the most dangerous skin cancer
because it spreads rapidly
 Usually occurs at site of a mole, which becomes
enlarged, mottled, and irregular in surface or borders
 Melanomas are most common on the back, chest,
abdomen, and lower legs
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
Cancers of the oral cavity, pharynx, larynx,
and nasal cavity
 Traced to cigarette, cigar, or pipe smoking, the use
of spit tobacco, and excessive consumption of
alcohol
 HPV infection linked to cancers of tonsils and tongue
 Head and neck cancers are twice as common in
men and occur most frequently in men over 40
 Chemotherapy, radiation, or surgery is used to treat
head and neck cancers
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
Testicular cancer is the most common cancer
among men ages 20 to 35, but it is rare
 Regular self-examination
 Tumors treated by surgical removal and, if the tumor
has spread, by chemotherapy
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45

Pancreatic cancer kills 49,000 Americans
annually
 Usually well advanced when detected
 There is no effective cure available

Bladder cancer
 Men are four times more likely to have it
 Smoking is a key risk factor
 Symptoms: blood in the urine, increased frequency
of urination
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
Kidney cancer usually occurs over 50
 Smoking, obesity, and family history are mild risk
factors
▪ Symptoms: fatigue, pain in the side, and blood in the urine

Brain cancer can arise from most cell types
found in the brain
 Ionizing radiation is a risk factor
 Some brain tumors are curable
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
Leukemia is cancer of the white blood cells
 Starts in bone marrow but can spread to other
organs and the central nervous system

Lymphoma is a form of cancer that begins in
the lymph nodes
 May spread to almost any part of the body
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
Detecting cancer
 Self-monitoring
▪ Be aware of risk factors
▪ Report changes to a physician
Centers for Disease Control and Prevention
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49

Stages of cancer
 Physicians need to know the exact size and location
of a tumor to treat it effectively
 Staging
▪ Cancer is categorized in five stages by judging the size or
extent, spread, and metastases
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STAGE
DESCRIPTION
0
Carcinoma in situ: abnormal cells are present only in the
layer of cells in which they developed; not cancer but
may become cancer
I, II, and III
Higher numbers indicate more extensive disease: Larger
tumor size and/or spread of the cancer beyond the
organ in which it first developed to nearby lymph nodes
or to tissues or organs adjacent to the primary tumor
IV
Cancer that has spread to distant tissues or organs
SOURCE: National Cancer Institute. 2015. Cancer staging (http://www.cancer.gov/about-
cancer/diagnosis-staging/staging/staging-fact-sheet).
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
Treating cancer
 Surgery
▪ For most cancers, surgery is the most useful treatment
 Chemotherapy
 Radiation
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CANCER SITE
APPROXIMATE PERCENTAGE OF APPROXIMATE PERCENTAGE OF
MALE DEATHS ATTRIBUTABLE TO FEMALE DEATHS ATTRIBUTABLE
SMOKING
TO SMOKING
Oropharynx
75% of 5,100 deaths
33% of 2,500 deaths
Larynx
80% of 3,000 deaths
75% of 600 deaths
Esophagus
70% of 9,700 deaths
55% of 3,000 deaths
Stomach
30% of 7,000 deaths
10% of 5,000 deaths
Pancreas
20% of 15,000 deaths
20% of 16,000 deaths
Lung
90% of 90,000 deaths
70% of 67,000 deaths
Bladder
45% of 8,500 deaths
25% of 4,000 deaths
Kidney
40% of 7,500 deaths
5% of 4,500 deaths
Myeloid leukemia
20% of 4,000 deaths
10% of 3,200 deaths
Cervix
Not applicable
10% of 3,800 deaths
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DO MORE OF:
•
•
•
•
•
•
•
•
•
Eat a varied, plant-based diet that is high in fiber-rich foods such as legumes and whole grains.
Eat 7–13 servings of fruits and vegetables every day, favoring foods from the following categories:
Cruciferous vegetables, Citrus fruits, Berries, Dark green leafy vegetables, and Dark yellow, orange, or red fruits
and vegetables.
Be physically active.
Maintain a healthy weight.
Practice safer sex (to avoid HPV infection).
Protect your skin from the sun with appropriate clothing and sunscreen.
Perform regular self-exams.
Obtain recommended screening tests and discuss with your physician any family history of cancer.
DO LESS OF:
•
•
•
•
•
•
•
•
•
Don’t use tobacco in any form, including Cigarettes, Spit tobacco, Cigars and pipes, Bidis and clove cigarettes.
Avoid exposure to environmental tobacco smoke.
Limit consumption of fatty meats and other sources of saturated fat.
Avoid excessive alcohol consumption.
Limit consumption of salt.
Don‘t eat charred foods, and limit consumption of cured and smoked meats and meat and fish grilled in a direct
flame.
Avoid occupational exposure to carcinogens.
Limit exposure to UV radiation from sunlight.
Avoid tanning lamps or beds.
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55
MEN
Cancer Type
New Cases
Deaths
Brain
12,900
8,940
Oral
32,670
6,010
Skin (melanoma)
46,610
9,120
Lung
115,610
86,380
Breast
2,350
440
Stomach
15,540
6,500
Liver
25,510
17,030
Pancreas
24,840
20,710
Colon and rectum
69,090
26,100
Urinary system
96,580
21,110
Prostate
220,800
27,540
Testes
8,430
380
Penis
1,820
310
Myeloma
14,090
6,240
Leukemia
30,900
14,210
Lymphoma
44,950
12,140
Other
16,660
24,480
Total
848,200
312,150
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CONTINUED…
56
WOMEN
Cancer Type
New Cases
Deaths
Brain
9,950
6,380
Oral
13,110
2,640
Skin (melanoma)
33,490
4,220
Lung
105,590
71,660
Breast
231,840
40,290
Stomach
9,050
4,220
Liver
10,150
7,520
Pancreas
24,120
19,850
Colon and rectum
63,610
23,600
Urinary system
42,130
9,860
Ovary
21,290
14,180
Uterus
54,870
10,170
Cervix
12,900
4,100
Myeloma
12,760
5,000
Leukemia
23,370
10,240
Lymphoma
35,950
8,800
Other
14,850
19,360
Total
810,170
277,280
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




Asymmetry: Is one half unlike the other?
Border irregularity: Does it have an uneven, scalloped edge rather
than a clearly defined border?
Color variation: Is the color uniform, or does it vary from one area
to another, from tan to brown to black, or from white to red to blue?
Diameter larger than 1/4 inch: At its widest point, is the growth as
large as, or larger than, a pencil eraser?
Evolving: A mole or skin lesion that looks different from the rest or
has any change in size, shape, color, elevation, or another trait, or
any new symptom such as bleeding, itching, or crusting.
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