2. DEFINITION
A term for diseases in which abnormal
cells divide without control and can invade nearby
tissues.
3. Cancer cells can also spread to other parts of the
body through the blood and lymph systems.
There are several main types of cancer. Carcinoma
is a cancer that begins in the skin or in tissues that
line or cover internal organs.
Sarcoma is a cancer that begins in bone, cartilage,
fat, muscle, blood vessels, or other connective or
supportive tissue.
4. Leukemia is a cancer that starts in blood-forming
tissue, such as the bone marrow, and causes large
numbers of abnormal blood cells to be produced
and enter the blood.
Lymphoma and multiple myeloma are cancers that
begin in the cells of the immune system.
7. - Cancer cells are self sufficient on growth factors:
This means that they can continue to proliferate
and divide independently, as opposed to normal cells that
need external growth factors.
- They can resist inhibitory signals that normally come from
neighboring cells.
- Resisting apoptosis is also a crucial attribute of a cancer
cell. - Stimulation of angiogenesis is very important since
the rapidly growing cancer needs a high amount of oxygen
and nutrients. The stimulation of angiogenesis also serves
as a way of metastasis
8. - Can multiply forever:
Normal cells go through senescence
through e.g. shortening of telomeres with every cell
division. Cancer cells however have telomerase that
will sustain the telomere length of the chromosomes
rendering the cell virtually immortal.
- Invade local tissues and metastasize:
This means that the cancer cells spread
throughout the body by sending out pioneer cells that
can form new metastases.
10. DIFFERENCE BETWEEN NORMAL CELLS AND
CANCER CELLS
MORPHOLOGY
Normal cells have
uniform shapes and sizes
Cancer cells have a large
variety of sizes and shapes
The nucleuses have irregular
structure and have relatively
small cytoplasm.
11. REPRODUCTION AND CELL DEATH
Cells stop dividing when
too much of its kind are
present.
These cells grow and
divide in a controlled
manner and follow a
predictable life cycle.
Normal cells undergo the
process of apoptosis –
self destruction if they
detect abnormalities and
damage in their
organelles.
Cancer cells don’t stop
growing resulting to
appearance of a tumor ( a
cluster of mutant cells)
13. ADHESION AND INVASION
These cells have
external membranes
that allow them to bond
with other cells
These cells have the
ability to invade or
spread to other parts of
the body by travelling
through the blood
stream or the lymphatic
system – metastasis
14. SPECIALIZATION
Normal cells start out
as immature cells and
mature with certain
specialized functions.
Cancer cells do not
mature, and undergo
apoptosis. Instead
these cells become
immature overtime.
Cancer cells are
primitive and they don’t
have specialized
functions
15. SIGNAL RECOGNITION
Normal cells recognize
signals. They know
when there are enough
new cells and stops
dividing.
Cancer cells don’t
recognize signals.
Hence these cells
erratically reproduce
mutated cells.
16. WARNING SIGNS OF CANCER
To remember the seven early warning signs
of cancer, think of the word CAUTION
Change in bowel or bladder habits.
A sore that does not heal.
Unusual bleeding or discharge.
Thickening or lump in the breast, testicles, or elsewhere.
Indigestion or difficulty swallowing.
Obvious change in the size, colour, shape, or thickness
of a wart, mole, or mouth sore.
Nagging cough or hoarseness.
17. The following symptoms may also
indicate the presence of some form of cancer:
Coughing-up blood
Persistent headaches
Unexplained loss of weight or appetite
Chronic pain in bones
Persistent fatigue, nausea, or vomiting
Persistent low-grade fever, either constant or
intermittent
Repeated instances of infection
18. EARLY DETECTION AND SCREENING OF
CANCER
Early detection of cancer greatly increases the chances for
successful treatment. There are two major components of
early detection of cancer: education to promote early
diagnosis and screening.
Recognizing possible warning signs of cancer and taking
prompt action leads to early diagnosis. Increased
awareness of possible warning signs of cancer, among
physicians, nurses and other health care providers as well
as among the general public, can have a great impact on
the disease.
19. Some early signs of cancer include lumps, sores
that fail to heal, abnormal bleeding, persistent
indigestion, and chronic hoarseness. Early
diagnosis is particularly relevant for cancers of the
breast, cervix, mouth, larynx, colon and rectum, and
skin.
20. SCREENING OF CANCER
Screening refers to the use of simple tests across a
healthy population in order to identify individuals
who have disease, but do not yet have symptoms.
Examples include breast cancer screening using
mammography and cervical cancer screening using
cytology screening methods, including Pap smears.
21. Screening programmes should be undertaken only
when their effectiveness has been demonstrated, when
resources (personnel, equipment, etc.) are sufficient to
cover nearly all of the target group, when facilities exist
for confirming diagnoses and for treatment and follow-
up of those with abnormal results, and when
prevalence of the disease is high enough to justify the
effort and costs of screening.
22. Based on the existing evidence, mass population
screening can be advocated only for breast and
cervical cancer, using mammography screening
and cytology screening, in countries where
resources are available for wide coverage of the
population.
23. Several ongoing studies are currently evaluating low cost
approaches to screening that can be implemented and
sustained in low-resource settings.
For example visual inspection with acetic acid may prove
to be an effective screening method for cervical cancer in
the near future. More studies that evaluate low cost
alternative methods to mammography screening, such as
clinical breast examination, are needed.
24. PREVENTION OF CANCER
Tobacco
Tobacco smoking causes many types of
cancer, including cancers of the lung, oesophagus, larynx
(voice box), mouth, throat, kidney, bladder, pancreas,
stomach and cervix. About 70% of the lung cancer burden
can be attributed to smoking alone. Second-hand smoke
(SHS), also known as environmental tobacco smoke, has
been proven to cause lung cancer in nonsmoking adults.
25. PHYSICAL INACTIVITY, DIETARY FACTORS, OBESITY
AND BEING OVERWEIGHT
Dietary modification is another important approach to cancer
control. There is a link between overweight and obesity to many
types of cancer such as oesophagus, colorectum, breast,
endometrium and kidney. Diets high in fruits and vegetables may
have a protective effect against many cancers. Conversely, excess
consumption of red and preserved meat may be associated with
an increased risk of colorectal cancer.
In addition, healthy eating habits that prevent the development of
diet-associated cancers will also lower the risk of cardiovascular
disease.
26. Regular physical activity and the maintenance of a
healthy body weight, along with a healthy diet, will
considerably reduce cancer risk. National policies and
programmes should be implemented to raise awareness
and reduce exposure to cancer risk factors, and to ensure
that people are provided with the information and support
they need to adopt healthy lifestyles.
27. Alcohol use
Alcohol use is a risk factor for many cancer
types including cancer of the oral cavity, pharynx, larynx,
oesophagus, liver, colorectum and breast. Risk of cancer
increases with the amount of alcohol consumed. The risk
from heavy drinking for several cancer types (e.g. oral
cavity, pharynx, larynx and oesophagus) substantially
increases if the person is also a heavy smoker.
28. Infections
Infectious agents are responsible for almost 22%
of cancer deaths in the developing world and 6% in
industrialized countries. Viral hepatitis B and C cause cancer of
the liver; human papilloma virus infection causes cervical
cancer; the bacterium Helicobacter pylori increases the risk of
stomach cancer.
In some countries the parasitic infection
schistosomiasis increases the risk of bladder cancer and in other
countries the liver fluke increases the risk of cholangiocarcinoma
of the bile ducts. Preventive measures include vaccination and
prevention of infection and infestation.
29. Environmental pollution
Environmental pollution of air,
water and soil with carcinogenic chemicals accounts
for 1–4% of all cancers (IARC/WHO, 2003). Exposure
to carcinogenic chemicals in the environment can
occur through drinking water or pollution of indoor
and ambient air.
30. Occupational cancinogens:
Occupational cancers are concentrated among
specific groups of the working population, for whom the risk
of developing a particular form of cancer may be much
higher than for the general population. About 20–30% of the
male and 5–20% of the female working-age population
(people aged 15–64 years) may have been exposed to lung
carcinogens during their working lives, accounting for about
10% of lung cancers worldwide. About 2% of leukaemia
cases worldwide are attributable to occupational exposures.
31. Radiation:
Residential exposure to radon gas from soil
and building materials is estimated to cause between 3%
and 14% of all lung cancers, making it the second cause of
lung cancer after tobacco smoke.
Ultraviolet (UV) radiation, and in particular
solar radiation, is carcinogenic to humans, causing all major
types of skin cancer, such as basal cell carcinoma (BCC),
squamous cell carcinoma (SCC) and melanoma.
