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What is cancer?
What causes cancer?
Can cancer be prevented?
What are some of the common signs and
symptoms of cancer?
Screening for cancer
How is cancer treated?
Where can I buy home test kits for contributing factors of
More information on cancer
What is cancer? (top)
Cancer is a group of many related
diseases that begin in cells, the body’s basic building blocks. To
understand cancer, it is helpful to know what happens when normal cells
The body is made up of many types of
cells. Normally, cells grow and divide to produce more cells as they are
needed to keep the body healthy. Sometimes, this orderly process goes
wrong. New cells form when the body does not need them, and old cells do
not die when they should. The extra cells form a mass of tissue called a
growth or tumor. Not all tumors are cancerous; tumors can be benign or
Benign tumors are not cancer. 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. Most important,
benign tumors are rarely a threat to life.
Malignant tumors are cancer. Cells
in malignant tumors are abnormal and divide without control or order.
Cancer cells invade and destroy the tissue around them.
Most cancers are named for where they
start. For example, lung cancer starts in the lung, and breast cancer
starts in the breast. Lymphoma is cancer that starts in the lymphatic
system. And leukemia is cancer that starts in white blood cells
causes cancer? (top)
Scientists have learned that cancer is
caused by changes in genes that normally control the growth and death of
cells. Certain lifestyle and environmental factors can change some
normal genes into genes that allow the growth of cancer. Many gene
changes that lead to cancer are the result of tobacco use, diet,
exposure to ultraviolet (UV) radiation from the sun, or exposure to
carcinogens (cancer-causing substances) in the workplace or in the
environment. Some gene alterations are inherited (from one or both
parents). However, having an inherited gene alteration does not always
that the person will develop cancer; it only means that the chance of
getting cancer is increased. Scientists continue to examine the factors
that may increase or decrease a person’s chance of developing cancer.
Although being infected with certain
viruses, such as the human papillomavirus (HPV), hepatitis B and C (HepB
and HepC), and human immunodeficiency virus (HIV), increases the risk of
some types of cancer, cancer itself is not contagious. A person cannot
catch cancer from someone who has this disease. Scientists also know
that an injury or bruise does not cause cancer.
cancer be prevented?
Although there is no guaranteed way to
prevent cancer, people can reduce their chance of developing cancer by
following the below:
Do not use tobacco products.
• Choose foods with less fat and eat more vegetables,
fruits, and whole grains.
Exercise regularly and maintain a lean
Avoid the harmful rays of the sun,
use sunscreen, and wear clothing that protects the skin.
Talk with a doctor about the possible
benefits of drugs proven to reduce the risk of certain cancers.
many risk factors can be avoided, some, such as inherited conditions,
are unavoidable. Still, it is helpful to be aware of them. It is also
important to keep in mind that not everyone with a particular risk
factor for cancer actually gets the disease; in fact, most do not.
People who have an increased likelihood of developing cancer can help
protect themselves by avoiding risk factors whenever
possible and by getting regular checkups so that, if cancer develops, it
is likely to be found and treated early. Treatment is often more
effective when cancer is detected early.
What are some of the common signs and
symptoms of cancer? (top)
Cancer can cause a variety of symptoms.
Possible signs of cancer include the following:
• New thickening or lump in the breast or any other part
of the body
• New mole or an obvious change in the appearance of an
existing wart or mole
• A sore that does not heal
• Nagging cough or hoarseness
• Changes in bowel or bladder habits
• Persistent indigestion or difficulty swallowing
• Unexplained changes in weight
• Unusual bleeding or discharge
When these or other symptoms occur, they
are not always caused by cancer. They can be caused by infections,
benign tumors, or other problems. It is important to see a doctor about
any of these symptoms or about other physical changes. Only a doctor can
make a diagnosis. A person with these or other symptoms should not wait
to feel pain because early cancer usually does not cause pain.
If symptoms occur, the doctor may perform
a physical examination, order blood work and other tests, and/or
recommend a biopsy. In most cases, a biopsy is the only way to know for
certain whether cancer is present. During a biopsy, the doctor removes a
sample of tissue from the abnormal area. A pathologist studies the
tissue under a microscope to identify cancer cells.
Some types of cancer can be found before
they cause symptoms. Checking for cancer (or for conditions that may
lead to cancer) in people who have no symptoms is called screening.
Screening tests are used widely to check
for cancers of the breast, cervix, colon, and rectum:
Breast: A mammogram is the
best tool doctors have to find breast cancer early. A mammogram is a
picture of the breast made with x-rays. The NCI recommends that women in
their forties and older have mammograms every 1 to 2 years. Women who
are at higher-than-average risk of breast cancer should talk with their
health care provider about whether to have mammograms before age 40 and
how often to have them.
Cervix: The Pap test
(sometimes called Pap smear) is used to check cells from the cervix. The
doctor scrapes a sample of cells from the cervix. A lab checks the cells
for cancer or changes that may lead to cancer (including changes caused
by human papillomavirus, the most important risk factor for cancer of
the cervix). Women should begin having Pap tests 3 years after they
begin having sexual intercourse, or when they reach age 21 (whichever
comes first). Most women should have a Pap test at least once every 3
Colon and rectum: A number
of screening tests are used to detect polyps (growths), cancer, or other
problems in the colon and rectum. People aged 50 and older should be
screened. People who have a higher-than-average risk of cancer of the
colon or rectum should talk with their doctor about whether to have
screening tests before age 50 and how often to have them.
Fecal occult blood test: Sometimes cancer or polyps bleed. This test can
detect tiny amounts of blood in the stool.
Sigmoidoscopy: The doctor checks inside
the rectum and lower part of the colon with a lighted tube called a
sigmoidoscope. The doctor can usually remove polyps through the tube.
Colonoscopy: The doctor examines inside
the rectum and entire colon using a long, lighted tube called a
colonoscope. The doctor can usually remove polyps through the tube.
Double-contrast barium enema: This
procedure involves several x-rays of the colon and rectum. The patient
is given an enema with a barium solution, and air is pumped into the
rectum. The barium and air improve the x-ray images of the colon and
Digital rectal exam: A rectal exam is
often part of a routine physical exam. The health care provider inserts
a lubricated, gloved finger into the rectum to feel for abnormal areas.
A digital rectal exam allows for examination of only the lowest part of
Doctors consider many factors before they
suggest a screening test. They weigh factors related to the test and to
the cancer that the test can detect. They also pay special attention to
a person's risk for developing certain types of cancer. For example,
doctors think about the person's age, medical history, general health,
family history, and lifestyle. They consider how accurate the test is.
In addition, doctors keep in mind the possible harms of the screening
test itself. They also look at the risk of follow-up tests or surgery
that the person might need to see if an abnormal test result means
cancer. Doctors also think about the risks and benefits of treatment if
testing finds cancer. They consider how well the treatment works and
what side effects it causes.
is cancer diagnosed? (top)
If you have a symptom or your screening
test result suggests cancer, the doctor must find out whether it is due
to cancer or to some other cause. The doctor may ask about your personal
and family medical history and do a physical exam. The doctor also may
order lab tests, x-rays, or other tests or procedures.
Tests of the blood, urine, or other
fluids can help doctors make a diagnosis. These tests can show how well
an organ (such as the kidney) is doing its job. Also, high amounts of
some substances may be a sign of cancer. These substances are often
called tumor markers. However, abnormal lab results are not a sure sign
of cancer. Doctors cannot rely on lab tests alone to diagnose cancer.
Your doctor may refer you to a surgeon or breast disease specialist for
a biopsy. Fluid or tissue is removed from your breast to help find out
if there is cancer.
Doctors can remove tissue from the breast in different ways:
Fine-needle aspiration: Your doctor uses a thin needle to remove
fluid from a breast lump. If the fluid appears to contain cells, a
pathologist at a lab checks them for cancer with a microscope. If the
fluid is clear, it may not need to be checked by a lab.
Core biopsy: Your doctor uses a thick needle to remove breast
tissue. A pathologist checks for cancer cells. This procedure is also
called a needle biopsy.
Surgical biopsy: Your surgeon removes a sample of tissue. A
pathologist checks the tissue for cancer cells.
An incisional biopsy takes a sample of a lump or abnormal area.
An excisional biopsy takes the entire lump or area.
If cancer cells are found, the
pathologist can tell what kind of cancer it is
Imaging procedure create pictures of
areas inside your body that help the doctor see whether a tumor is
present. These pictures can be made in several ways:
• X-rays: X-rays are the most common way to view organs
and bones inside the body.
• CT scan: An x-ray machine linked to a computer takes a
series of detailed pictures of your organs. You may receive a contrast
material (such as dye) to make these pictures easier to read.
• Radionuclide scan: You receive an injection of a small
amount of radioactive material. It flows through your bloodstream and
collects in certain bones or organs. A machine called a scanner detects
and measures the radioactivity. The scanner creates pictures of bones or
organs on a computer screen or on film. Your body gets rid of the
radioactive substance quickly.
• Ultrasound: An ultrasound device sends out sound waves
that people cannot hear. The waves bounce off tissues inside your body
like an echo. A computer uses these echoes to create a picture called a
• MRI: A strong magnet linked to a computer is used to
make detailed pictures of areas in your body. Your doctor can view these
pictures on a monitor and can print them on film.
• PET scan: You receive an injection of a small amount of
radioactive material. A machine makes pictures that show chemical
activities in the body. Cancer cells sometimes show up as areas of high
How is cancer treated? (top)
Cancer treatment can include surgery,
radiation therapy, chemotherapy, hormone therapy, and biological
therapy. The doctor may use one method or a combination of methods,
depending on the type and location of the cancer, whether the disease
has spread, the patient’s age and general health, and other factors.
Because treatment for cancer can also damage healthy cells and tissues,
it often causes side effects. Some patients may worry that the side
effects of treatment are worse than the disease. However, patients and
doctors generally discuss the treatment options, weighing the likely
benefits of killing cancer cells and the risks of possible side effects.
Doctors can suggest ways to reduce or eliminate problems that may occur
during and after treatment.
Surgery is an operation to
remove cancer. The side effects of surgery depend on many factors,
including the size and location of the tumor, the type of operation, and
the patient’s general health. Patients have some pain after surgery, but
this pain can be controlled with medicine. It is also common for
patients to feel tired or weak for a while after surgery.
Patients may worry that having a biopsy
or other type of surgery for cancer will spread the disease. This is a
very rare occurrence because surgeons take special precautions to
prevent cancer from spreading during surgery. Also, exposing cancer to
air during surgery does not cause the disease to spread.
Radiation therapy (also
called radiotherapy) uses high-energy rays to kill cancer cells in a
targeted area. Radiation can be given externally by a machine that aims
radiation at the tumor area. It can also be given internally; needles,
seeds, wires, or catheters containing a radioactive substance are placed
directly in or near the tumor. Radiation treatments are painless. The
side effects are usually temporary, and most can be treated or
controlled. Patients are likely to feel very tired, especially in the
later weeks of treatment. Radiation therapy may also cause a decrease in
the number of white blood cells, which help protect the body against
infection. With external radiation, it is also common to have temporary
hair loss in the treated area and for the skin to become red, dry,
tender, and itchy.
There is no risk of radiation exposure
from coming in contact with a patient undergoing external radiation
therapy. External radiation does not cause the body to become
radioactive. With internal radiation (also called implant radiation), a
patient may need to stay in the hospital, away from other people, while
the radiation level is highest. Implants may be permanent or temporary.
The amount of radiation in a permanent implant goes down to a safe level
before the person leaves the hospital. With a temporary implant, there
is no radioactivity left in the body after the implant is removed.
Chemotherapy is the use of
drugs that kill cancer cells throughout the body. Healthy cells can also
be harmed, especially those that divide quickly. The doctor may use one
drug or a combination of drugs. The side effects of chemotherapy depend
mainly on the drug(s) and the dose(s) the patient receives. Hair loss is
a common side effect of chemotherapy; however, not all anticancer drugs
cause loss of hair. Anticancer drugs may also cause temporary fatigue,
poor appetite, nausea and vomiting, diarrhea, and mouth and lip sores.
Drugs that prevent or reduce nausea and vomiting can help with some of
these side effects. Normal cells usually recover when chemotherapy is
over, so most side effects gradually go away after treatment ends.
Hormone therapy is used to
treat certain cancers that depend on hormones for their growth. It works
by keeping cancer cells from getting or using the hormones they need to
grow. This treatment may include the use of drugs that stop the
production of certain hormones or that change the way hormones work.
Another type of hormone therapy is surgery to remove organs that make
hormones. For example, the ovaries may be removed to treat breast
cancer, or the testicles may be removed to treat prostate cancer.
Hormone therapy can cause a number of
side effects. Patients may feel tired, or have fluid retention, weight
gain, hot flashes, nausea and vomiting, changes in appetite, and, in
some cases, blood clots. Hormone therapy may also cause bone loss in
premenopausal women. Depending on the type of hormone therapy used,
these side effects may be temporary, long lasting, or permanent.
Biological therapy uses the
body’s immune system, directly or indirectly, to fight disease and to
lessen some of the side effects of cancer treatment. Monoclonal
antibodies, interferon, interleukin-2, and colony-stimulating factors
are some types of biological therapy.
The side effects caused by biological
therapy vary with the specific treatment. In general, these treatments
tend to cause flu-like symptoms, such as chills, fever, muscle aches,
weakness, loss of appetite, nausea, vomiting, and diarrhea. Patients
also may bleed or bruise easily, get a skin rash, or have swelling.
These problems can be severe, but they go away after the treatment
Where can I buy home test kits for contributing factors of cancer? (top)
Click here to purchase a home test kit for cancer
More information on
For additional information on cancer,
please visit the below links to the
National Cancer Institute
A to Z list of
Finding clinical trials