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Chapter 16
Figure 16.1 Percentage of all cancer deaths linked
to risk factors
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 Definition:
An abnormal and uncontrolled
growth of cells that can lead to death
 Tumor: A mass of tissue that serves no
physiological purpose
 Benign tumor: Mass of cells enclosed in
a membrane that prevents their
penetration of other tissues
 Malignant tumor: Mass of cells that can
invade surrounding tissues
 Every case of cancer begins as a genetic
change in a cell that allows it to grow
and divide when it should not.
 Definition:
The spread of cancer cells
from one part of the body to another
 Primary tumor: original location of cancer
 Secondary tumors: New tumors
Figure 16.2 Tumor development occurs in
stages
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Stage
Description
0
Early cancer, present only where
it originated
I
More extensive
II
Greater tumor size
III
Cancer has spread to nearby
lymph nodes/adjacent organs
IV
Advanced cancer; spread to
other organs
Staging is based on size
Classified
according to types of cells
that give rise to them
 Carcinomas
– arise from epithelial tissue
Ex., skin
 Sarcomas – arise from connective tissue
 Bone, cartilage, etc.
 Lymphomas- arise from lymph nodes
 Leukemias - Cancer of the bloodforming cells in bone marrow.

American
Cancer Society Estimates:
 90%
of skin cancer could have been
prevented by protecting the skin from
the sun
 87% of lung cancer could be prevented
by avoiding exposure to tobacco smoke
Regular
screening and selfexaminations could save an
additional 100,000 lives per year.
 Leading
U.S.

cause of cancer deaths in the
~158,000 deaths/year
 Risk
factors
 Tobacco smoke (including ETS)
contributes to 90% of lung cancer deaths
 Detection



Symptoms: Persistent cough, chest pain, or
recurring bronchitis
Difficult to detect early and symptoms usually
do not appear until the invasive stage
Diagnosis: CT scan, chest x-ray or sputum
examination, bronchoscopy
 Treatment

If caught early, localized cancers can be
treated with surgery
A
combination of radiation and/or
chemotherapy can be used in addition to
surgery
 Risk
factors
Age (91% of cases occur in
people 50 or older)
 Heredity, genetic propensity to
develop polyps
 Diet, smoking, excessive
alcohol use and obesity

 Detection
and treatment
 Symptoms:
bleeding from rectum and
changes in bowel habits
 Regular screening tests are
recommended beginning at age 50
 Treatment
 Primarily
Surgery
 Radiation and chemotherapy
can be used
Most
common cancer in women
Causes almost as many deaths in
women as lung cancer
Risk factors
Strong genetic factor: inheriting
mutated BRCA1/2 genes
 Age: Most common in women over
50
 Early onset of menstruation
 First child after 30
 Current use of HT
 Unhealthy diet and lifestyle


Detection
 Symptoms may include a lump,
changes in size, dimpled, redness
or a scaly of nipple or breasts
ACS recommends 1
mammogram/year (women over
40)
 Clinical and Self breast exams
(starting at age 20)

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
Treatment
 A cure is most
likely if detected
early
 Removal of the
tumor if
discovered
before it has
spread.
Most
men
Risk
common cancer in
factors
 Age (more than 60%
of cases diagnosed in
men over 65)
 Genetic
predisposition
 Diet and Lifestyle
 African American and
Jamaican men have
highest rates in the
world
Detection
 Symptoms
may include changes in
urinary frequency, weak or
interrupted urine flow, painful
urination, blood in urine
 Blood
test: Prostate-specific
antigen (PSA)
 Rectal exam
Treatment
 Surgical removal of the prostate and
radiation (depends on stage and age)
 Radioactive seeds
Cervical cancer
 Most cases stem
from human
papillomavirus (HPV) infection
(STD)
 Prevention
The PAP test is a highly effective
screening test for this cancer
 All sexually active women ages 18-65
should be tested regularly
 A vaccine against HPV is Gardasil

Main types of skin cancer
 Basal cell carcinomas
 Squamous cell carcinomas
 Melanoma (most deadly type)
Most common form of cancer
 1 million cases per year (68,000 are
melanoma)
Risk
factors
 Excessive exposure to UV rays
 Pale skin, easily sunburned
 Caucasians are 10X more likely
than
African Americans to develop basal and
squamous cell carcinoma
Prevention
 Avoid long
term
overexposure
to sunlight
Detection
Melanoma
 ABCD
test
of
screen

The role of DNA mutations and Cancer
Mutagens: substances that cause mutations like
radiation, certain viruses, ingested chemicals,
environmental pollution
 Oncogenes: A gene in which mutations are associated
with the transformation of a normal cell into a cancer
cell
 Tumor suppressor gene: Type of oncogene that
normally restricts cellular growth


Hereditary cancer risks
If a hereditary cancer, abnormal gene is present in
sperm/egg
 If not hereditary, a mutation has occurred

Tobacco Use
 Dietary Factors -fried foods, low fiber, lack of
phytochemicals from fruits and vegetables.
 Inactivity and Obesity

 Cancer

promoters
Cancer promoters do not directly produce
mutations, instead they accelerate the growth of
cells without damaging or permanently altering
the DNA

Estrogen is an example
Figure 16.8 The seven major warning signs of
cancer
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Preventing Cancer

Lifestyle choices
 Avoid tobacco
 Control diet and weight
 Regular exercise
 Protect skin from the sun
 Avoiding environmental and occupational
carcinogens
 Follow recommendations for cancer
screenings
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