Canadian Cancer Statistics
1 in 4 deaths are due to cancer
Based on 2009 incidence rates, 40% of
Canadian women and 45% of men will
develop cancer during their lifetimes
Lung cancer remains the leading
cause of cancer death for both men
and women
Prostate cancer is the most common
cancer among Canadian men
Breast cancer is the most common
Cancer
Cancer can develop anywhere in
the body, and at any age
Unlike infectious diseases such as
AIDS or the flu (influenza),
cancer
is NOT contagious
There are over 100 different forms
of cancer
CQ1: What is the difference between
cancer
and
tumor
? What do you
think?
3
A: The two terms can be used interchangeably as they are synonymous.
B: Cancer is a disease that eventually disrupts body functions whereas a tumor is a mass of cells with no apparent function in the body. C: Cancer is a disease which affects men
whereas a tumor may affect both men and women.
D: Cancer is a disease of the digestive tract
What is Cancer?
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Simplest definition
From the American Cancer Society
“ cancer is a group of diseases characterized by
uncontrolled growth and spread of abnormal cells. If the spread is not controlled, it can result in death.”
Tumor
Two types:
Benign (non-cancerous)
Does not spread; though it can eventually become malignant in some cases.
Malignant (cancerous)
Has the potential to spread to other parts of body.
CQ2: How do cancer cells travel
through the human body?
5
A: Cancer travels through the body by way of sexual intercourse between a healthy person and one affected by the disease.
B: The circulatory system only is responsible for relocating cancer cells.
C: The lymphatic system collects fluids from capillaries and with it cancer cells, which are then delivered by the circulatory system.
Normal versus Abnormal
The division of
normal cells is
precisely controlled
New cells are only
formed for growth or to replace dead
ones
Cancerous cells
divide repeatedly out of control even though they are not needed
Cancerous cells
crowd out other normal cells and
function abnormally
This can destroy the
surrounding body tissues and the
correct functioning of major organs
9
Role of Cell Division in Cancer
Top
= normal cell division
Bottom
= unregulated cell
division and tumor
formation
Malignant
If tumor invades surrounding tissue
(cancerous)
Metastatic
If individual cells break away and start a new
tumor elsewhere (cancerous)
Benign
If tumor has no effect on surrounding tissue
(non-cancerous)
Some terms:
A factor which brings about a mutation is
called a mutagen.
A mutagen is mutagenic.
Any agent that causes cancer is called a
carcinogen and is described as carcinogenic.
Mutations in cells can be triggered by
UV radiation
chemical exposure radiation exposure Virus infection (HPV)
cigarette smoke pollution
age
genetics
Genetic?
Hereditary predisposition
–
Some families are
more
susceptible
to getting certain
cancers.
Remember
you can’t inherit
cancer
- its just that you may be
more susceptible to getting it
You have similar genes with
similar vulnerabilities, and have
grown up in the same
From Benign to Malignant
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Cancer cells divide too quickly and can
leave the original site and enter the
blood, lymph, or tissues.
Most cells divide a set number (60-70)
of times, then they stop dividing.
This usually limits benign tumors to
small sizes.
14
The vessels of the circulatory and lymphatic systems provide a pipeline for cancer cells to move to other
CQ3: Can surgery successfully cure a
cancer that has metastasized?
15
A.
No, all body cells are dividing
uncontrollably
B.
Yes, it could remove all cells with
defective cell-cycle regulation
C.
No, cancer cells are no longer
localized in one spot
Tumor cells travel: Metastasize
What makes most
tumours so lethal is
their ability to
metastasize
through the blood
and lymph
that is, establish new
tumour sites at other locations throughout the body
Secondary tumours
Most of these cells will
die soon after entering the blood or lymph
circulation
Secondary Tumors
To form a secondary tumour, a tumour cell
needs to leave the vessel system and invade tissue.
The cell must attach itself to a vessel's wall.
Once this is done, it can work its way through the vessel wall and enter the tissue.
Perhaps less than one in 10,000 tumour cells
Three basic treatments:
surgery to remove the
tumor, and radiation or
chemicals (chemotherapy)
to kill actively dividing cells.
It is hard to remove all the
tumor cells.
Tumors often lack sharp
boundaries for easy removal, and metastatic tumors can be very small (pin-head) and
Cancer Detection
and Treatment
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Earlier detection
and treatment of cancer greatly
increase the odds of survival.
Therefore, knowing
the warning signs of cancer is
important to health.
C hange in bowel or bladder habits
A sore that does not heal
U nusual bleeding or discharge
T thickening or lump
I ndigestion or difficulty swallowing
O bvious change in wart or mole
Skin Cancer
What does
it look like?
ABCD Look For’s
Asymmetry
Border
Colour
Diameter
Preventing Cancer
1. As mentioned before, early detection is essential
screening for cervical, colorectal and breast cancers and self-exam for testicular cancer
2. Make healthy choices – avoid tobacco, limit alcohol use,
protect skin from UV (sun), eat a healthy diet (lots of fruit vegetables), maintain a healthy weight and be physically active
3. Vaccines
HPV Cervical cancer; Hep B Liver cancer
YOUR GENERATION…
Is the first generation to benefit from a new
vaccine against HPV.
Why is this so important?
40% of the female population are infected at any time HPV is a STI that predisposes women to cervical and
ovarian cancer
The highest rates of infection are among people under
25
Besides abstinence, the vaccine is your best
protection, otherwise condoms are the only
