2. Cancer
• Cancer is a term used
for diseases in which
abnormal cells divide
without control and are
able to invade other
tissues. Cancer cells
can spread to other
parts of the body
through the blood and
lymph systems. • Cancer harms the body when
damaged cells divide uncontrollably
• Cancer is a class of to form lumps or masses of tissue
diseases characterized called tumors .
by out-of-control cell
growth. There are over
100 different types of
cancer, and each is
classified by the type of
cell that is initially
3. Not all tumors are cancerous;
tumors can be:
a. Benign
Benign tumors aren't cancerous. They can often
be removed, and, in most cases, they do not
come back. Cells in benign tumors do not spread
to other parts of the body.
b. Malignant
Malignant tumors are cancerous. Cells in
these tumors can invade nearby tissues
and spread to other parts of the body. The
spread of cancer from one part of the body
to another is called metastasis.
4. What causes cancer?
Cancer is ultimately the result of cells that
uncontrollably grow and do not die. Normal
cells in the body follow an orderly path of
growth, division, and death. Programmed
cell death is called apoptosis, and when
this process breaks down, cancer begins
to form. Unlike regular cells, cancer cells
do not experience programmatic death
and instead continue to grow and divide.
This leads to a mass of abnormal cells that
grows out of control.
5. • Genes- the DNA type
Cells can experience uncontrolled growth
if there are damages or mutations to
DNA, and therefore, damage to the genes
involved in cell division. Four key types of
gene are responsible for the
cell division process: oncogenes tell cells
when to divide, tumor suppressor genes
tell cells when not to divide, suicide genes
control apoptosis and tell the cell to kill
itself if something goes wrong, and DNA-
repair genes instruct a cell to repair
damaged DNA.
6. • Carcinogens
Carcinogens are a class of substances
that are directly responsible for damaging
DNA, promoting or aiding cancer. Tobacco,
asbestos, arsenic, radiation such as
gamma and x-rays, the sun, and
compounds in car exhaust fumes are all
examples of carcinogens. When our
bodies are exposed to carcinogens, free
radicals are formed that try to steal
electrons from other molecules in the
body. Theses free radicals damage cells
and affect their ability to function normally.
7. • Genes- family type
Cancer can be the result of a genetic
predisposition that is inherited from
family members. It is possible to be
born with certain genetic mutations or a
fault in a gene that makes one
statistically more likely to develop
cancer later in life.
8. • Other medical factors
As we age, there is an increase in the number of
possible cancer-causing mutations in our DNA.
This makes age an important risk factor for cancer.
Several viruses have also been linked to cancer
such as:
a. human papillomavirus (a cause of cervical
cancer)
b. hepatitis B and C (causes of liver cancer)
c. Epstein-Barr virus (a cause of some childhood
cancers).
d. Human immunodeficiency virus (HIV) - and
anything else that suppresses or weakens the
immune system - inhibits the body's ability to
fight infections and increases the chance of
developing cancer.
9. • How is cancer diagnosed and
staged?
Early detection of cancer can greatly
improve the odds of successful treatment
and survival. Physicians use information
from symptoms and several other
procedures to diagnose cancer. Imaging
techniques such as X-rays, CT scans, MRI
scans, PET scans, and ultrasound scans
are used regularly in order to detect where
a tumor is located and what organs may
be affected by it. Doctors may also
conduct an endoscopy, which is a
procedure that uses a thin tube with a
camera and light at one end, to look for
abnormalities inside the body.
12. How can cancer be
prevented?
A person's cancer risk can be reduced
in other ways by receiving regular
medical care, avoiding tobacco, limiting
alcohol use, avoiding excessive
exposure to ultraviolet rays from the sun
and tanning beds, eating a diet rich in
fruits and vegetables, maintaining a
healthy weight, and being physically
active.
13. Effective Cancer Prevention
Measures
Opportunities exist to reduce cancer risk and prevent
some cancers. Cancer risk can be reduced by avoiding
tobacco, limiting alcohol use, limiting exposure to
ultraviolet rays from the sun and tanning beds, eating a
diet rich in fruits and vegetables, maintaining a healthy
weight, being physically active, and seeking regular
medical care. Research shows that screening for cervical
and colorectal cancer at recommended intervals can
prevent these diseases by finding lesions that can be
treated before they become cancerous. Screening also
can help find cervical, colorectal, and breast cancers at an
early, treatable stage. Vaccines also can reduce cancer
risk. The human papillomavirus (HPV) vaccine helps
prevent some cervical, vaginal, and vulvar cancers. The
hepatitis B vaccine can reduce liver cancer risk. Making
cancer screening, information, and referral services
available and accessible to all Americans can reduce
cancer incidence and deaths.
15. • Primary prevention
Primary prevention, which aims to
reduce or eliminate exposure to cancer-
causing risk factors, will be critical for
controlling cancers in developing
countries. The most important
prevention measures are the following:
16. Immunization against or treatment of
infectious
agents associated with cancers.
*Two vaccines are particularly
important: a human papilloma virus
(HPV) vaccine to prevent infection from
certain types of the virus that can lead
to cervical cancer, and Hepatitis B to
help prevent liver cancer. The HPV
vaccine can potentially prevent about
70 percent of cervical cancer cases.
17. National tobacco and alcohol control programs.
* Tobacco use is the most important cause
of
cancers of the lung and respiratory system and
the
esophagus, and it contributes to several other
cancers.
Excessive alcohol consumption accounts for 20
percent to 30 percent of liver and esophageal
cancers.
Effective tobacco and alcohol control programs
include increasing taxes on the
products, restricting
or banning advertising and promotion, banning
smoking in public places, educating the public
about
the health risks of excessive use, and making
18. Programs to promote diets that
include more fruits and vegetables
and fewer harmful fats and
processed foods.
*Promoting healthy diets and exercise
can take place in schools and work
sites and through other public health
campaigns. Promoting healthy lifestyles
and curbing obesity can reduce the risk
of cancer as well as the risk of many
other (particularly cardiovascular)
diseases.
19. • Secondary prevention
Early Detection of Cancer
*The main objective of making cancer screening
widely
available is to detect cancer cases early enough to make
curative treatment possible. Screening for liver, stomach,
lung, and colorectal cancers have focused on people at
higher
risk for those cancers (for example, people over age 50
and
smokers), but the value of early detection varies greatly
with
the type of cancer. For example, screening for liver
cancer
can result in earlier diagnosis, but because treatment of
that
cancer is largely ineffective, screening has not been
20. Cancer prevention is an essential
component of all cancer
control plans because about 40% of all
cancer deaths can
be prevented.
