Chapter 12
Cancer
Reducing Your Risks
CANCER
NON-COMMUNICABLE DISEASES
CANCER
a large collection of Illnesses
• ONE COMMON TRAIT
• a loss of cell cycle control
• A SINGLE abnormal cell
replicates to create others
like itself
• Cluster into a Mass
Cancerous / Malignant
• Can travel through the
blood stream
• Cancer probably in
everyone - single cell
• Immune system
intervention
Cells Out Of Control
• Cell division is controlled
rigorously
• Cell stops LISTENING to
controls
• Gene #1- Oncogenes promote cell division
• Gene #2 - Tumor
Suppressor - inactivate or
remove constraints on cell
division
• Cells from Henrietta
Lacks, 1951- still
dividing and used in
many laboratories
• A few of her cells will
take over other tissues
in the lab
• Divide faster than
their natural state
• ….., don’t stop
Genes Out Of Control
• Proto-oncogenes - promote positive
controlled cell division
• Add a Mutation and the Gene Changes
to an ONCO (cancer) GENE
• Tumor Suppressor Genes - Chromosomal
deletions and loss of gene function
CHARACTERISTICS
• Tumors grow at fast
rates
• Early detection
imperative (size of a
pea)
• If 99% of a Tumor is
removed - millions of
cancer cells remain
• Transplantable movement within the
body - other tissues!
DEDIFFERENTIATED
• Skin - rounder, softer +
colour
• Density-Dependent
Inhibition - don’t stop
when over crowed
• Invasiveness - squeeze into
available space
• Anchor to Basement
Membranes - secrete
chemicals / cut through
healthy tissue
Inherited vs. Sporadic Cancer
• Cancer Susceptibility
Gene is passed on to
children
• Constitutional
mutation present in
every cell not active!
• Until a Second
Mutation Occurs
• Smokers - some
develop cancer
• many do not
• Sporadic Cancer is
not passed to
children
• TWO
INDEPENDENT
MUTATIONS
required
Cancer
• 2nd leading cause of
death approximately
(60,700) Canadians died
in 1997 from cancer
• 1/3 related to tobacco
• 72% in people older
than 60 years of age
Three Groups – a survival rating!
• Good Prognosis – breast, prostrate,
bladder, melanoma, body of the uterus,
cervix, Hodgkin’s Disease, testes, and male
bladder
• Fairly good prognosis – colorectal,
non-Hodgkin’s lymphoma, kidney, oral,
larynx, female bladder.
• Poor prognosis – lung, stomach, adult
leukemia, pancreas, ovary, brain, and
multiple myeloma
Cancer Risk……..
• Risk = not equal /
reflects age, sex, race,
socioeconomic status
• responsible for
majority of deaths -
children 3-14 years
of age than any other
disease
Terminology
• neoplasm – new growth of tissues / no
physiological function related to
original cells / tissues
• cells undergo abnormal change and
grow into tumors (either benign or
malignant)
• mutant cells – differ from original
cells in form, quality, or function
• malignant tumors are cancerous;
interfere with RNA/DNA in nucleus,
causing cells to grow out of control or
unregulated growth
Terminology
• benign tumors are not
cancerous; however, benign
tumors must be watched
carefully - can change
• biopsy (remove a section) –
only way to determine if
tumor is malignant
• oncogenes – suspected cancer
causing genes present in
chromosomes
Terminology…..continued
• proto-oncogenes – genes
with the potential to
become oncogenes
• oncologists – physicians
who specialize in the
treatment of malignancies
CANCER DEVELOPMENT:
• Localized / pea size ( Best Time
to Remove or Treat)
• progresses to surroundings
regions
…….IF NOT DETECTED
THEN…….METASTASIS!!!
• detached cancer cells that are
spread to other parts of body
in lymph or blood systems
• if removed - millions of cancer
cells remain!!!!!
WHAT CAUSES CANCER ?
• Hereditary AND/OR
Environmental
Immune theory:
• cancerous cells appear in body
randomly and usually dealt with
by immune system
• weakened immune system – let
these cells take hold
• factors such as vitamin status,
extreme chronic fatigue, stress and
carcinogens
WHAT CAUSES CANCER?
Virus theory:
• associated with some
animal cancers and
several human cancers
• most humans carry
viruses that have
cancer-causing
potential normally
dormant
• Viral - Hepatitis B,
AIDS.
Cancer Causing Agents
Carcinogens:
Mutating Genes
• environmental
factors e.g. radiation,
asbestos, industrial
solvents, tar, coal
dust, tobacco, etc.
FACTORS ASSOCIATED WITH
CANCER DEVELOPMENT
Biological causes:
• genetic link - familial patterns
• family history – certain types of
cancer run in families
• gender - breast, stomach, colon,
and prostate cancers
• cell mutations (lung cancer was
unheard of in women - but now
present as a result of tobacco)
Biological Reasons
• chemicals in processed
food – sodium nitrate
(prevents botulism) >
nitrosamines formed during
digestion >cancer causing
factors
• agricultural practices –
pesticide / herbicide >
residue on produce.
Occupational Factors:
• asbestos / radiation / coal
tar / certain dyes, etc, etc.
• about 5% of all cancers
from occupational factors
• construction, automotive,
insulation / industrial
waste
Psychosocial Factors:
Psychosocial factors:
• a negative emotional
state may aggravate
the disease process e.g.
lonely/depressed
• also lifestyle e.g. stress,
substances,
exercise/lack of
exercise
Diet
Diet:
• low fiber high meat
diets in particular
• may account for 60%
of cancer in women
and 40% in men.
RECOMMENDATIONS FOR PREVENTION
Nutrition
• reduce fat
• eat appropriate amounts of fiber
• sufficient vitamins A & C
• sufficient vegetables (roughage)
• reduce consumption of salt and
salt-cured foods
• maintain healthy weight
• moderate alcohol consumption
COMMON CLASSIFICATIONS
OF CANCER
CARCINOMAS:
• cancer of epithelial cells
- tissues covering body
surfaces and lining body
cavities:
• mouth
• skin
• lung
• breast
SARCOMAS……………..
• Cancer of mesodermal
layer (middle layers of
tissues) such as bone,
connective tissue and
layers of tissues
• metastasize – via blood
during early stages
• rare form of cancer (solid
tumor)
LYMPHOMAS
• Cancer of the lymph
system, e.g. Hodgkin's
disease
• the infection fighting
regions of the body
• solid tumors
LEUKEMIA
• Cancer of blood
forming parts of
body such as bone
marrow and spleen
• non-solid tumor
formation
• dramatic increase in
White Blood Cells
COMMON CANCER SITES
LUNG
• leading cause of death due
to cancer for men and
women = smoking
• smoking 90% of male lung
cancers, 79% of female
lung cancers
• smokers have 12 to 25
times the death rates of
non-smokers
Lung Cancer
• incidence of lung cancer in
females increasing
• symptoms are persistent
cough, chest pain, and
recurring
pneumonia/bronchitis
• surgery the treatment of
choice
• prognosis poor
• one third experience
metastasis
Fresh Air……… !!!
• difficult to treat
• only 13% alive and well
after 5 years from
diagnosis
• prevention: quit
smoking
BEST PREVENTION
Don’t START!!!!!!
COLON AND RECTUM:
• high incidence
• ulcerative colitis (ulceration
and inflammation of large
intestine) and congenital
polyposis (polyps, tumors,
grow in rectum)
• diet - low fiber / high
processed
• symptoms: rectal bleeding,
constipation or diarrhea,
abdominal discomfort
COLON AND RECTUM:
• stoma: surgically designed
opening / abdominal wall to
excrete body wastes collected
in a bag
• Treatment: Surgery
(colostomy) - rectum and
part of colon
• Radiation and
Chemotherapy
• Prevention: healthy diet,
exercise & testing
BREAST CANCER:
• leading site of cancer in
women
Risks: family history
• smoking
• first child after age 30
• lump in breast or
discharge from nipple
• age over 35
Breast Cancer…. Treatment:
lumpectomy
Simple mastectomy
(remove entire breast)
Modified Radical
Mastectomy (remove breast,
and lymph nodes of armpits)
Radical Mastectomy (remove
breast, lymph nodes and muscles)
UTERINE CANCER:
• cancer of cervix (neck of
uterus) and endometrium
(body of uterus)
• most preventable is cancer
of cervix
• greatest in low socioeconomic groups
• multiple sex partners
• Pap test - diagnose undetected in pre-cancerous
state
PROSTATE CANCER
• men over 50
• symptoms = urinary
obstruction / urinary
infections
• surgery primary
treatment
• drugs to shrink
tumor
TESTICULAR CANCER
• occurs in late
adolescence and early
adulthood
• genetic predisposition
• early detection / self
examination
SKIN CANCER - SEVERAL TYPES
(Malignant Melanoma)
basal and squamous = highly curable
melanomas are serious - dark brown
or black pigmentation
risks: fair skin; tanning salons, sun
lamps and sunbathing are high-risk
behaviors
sun-block / stay out of the sun!
treatment: surgery / radiation /
cryotherapy
Perception that a Tan looks healthy
ABC&D’s of Moles
• A - asymmetry
(1/2 different other 1/2)
• B - border irregularity
(ragged, uneven, dimpled)
• C - Colour
(Pigmentation not uniform)
• D - Diameter (<6mm)
ORAL:
• Cancer- lips, lining of
cheeks, gums, tongue
& throat
• Chewing tobacco
• Smoking tobacco
LEUKEMIA
• Cancer - blood forming tissues immature white blood cells crowd
other cells (WBCs, RBCs, Platelets
etc)
• Affect men + women / all ages
• symptoms:
• enlarged lymph nodes /spleen / liver
• fatigue / weight loss / frequent
infections / easy bruising and
nosebleeds
BIOPSY
• sample of tumor removed
for analysis
• best results when cancer is
localized
• early detection of cancer
best
• removal of the tumor +
other treatments if
spreading
CANCER TREATMENT
CHEMOTHERAPY
• use of drugs to treat
• works very well for
some forms of cancer
• many side effects not pleasant!
RADIOTHERAPY:
x-ray treatment
x-rays - destroy
abnormal cells
x-rays - minimal effect
on normal cells
IMMUNOTHERAPY
• enhances body's
immune response to
cancer cells
Stress
• since cells are from the
host body immune
system may not
recognize and attack
cancer cells
CANCER'S SEVEN WARNING
SIGNALS
• a change in bowel or bladder habits
• a sore that does not heal
• unusual bleeding or discharge
• thickening or lump in breast or elsewhere
• indigestion or difficulty swallowing
• obvious change in wart or mole
• nagging cough or hoarseness
If you have a warning signal see your doctor!
PREVENTION IS THE KEY
• DON'T smoke……….
if you do then QUIT!!!!!!
• Eat a balanced diet
• Regular checkups
• Investigate any lumps or sores
• Protect against excess sunlight
• Avoid cancer-producing substances (if possible)
• Self examinations