|
|
|
 |
|
| Detailed Guide: Bile Duct Cancer |
How Is Bile Duct Cancer Diagnosed? |
|
Signs and Symptoms of Bile Duct Cancer
The most common symptom of bile duct cancer is jaundice. Jaundice
occurs when the liver cannot get rid of bile, and one of the chemicals
in bile called bilirubin "backs up" into the bloodstream. Bilirubin is
greenish yellow and colors all the body tissues, including the skin and
the white part of the eyes, making people with this condition begin to
look
yellow. Because bilirubin also contributes to the brown coloring of
bowel movements, the blockage of its flow into the intestine might
lighten the color of one's stool. Bilirubin will also come out in the
urine and turn
it dark.
Bile and bilirubin also cause itching.
Jaundice is almost always due to hepatitis or to blockage of the bile
duct. It is important to realize that most causes of bile duct blockage
are not caused by cancer. Most often a stone in the bile duct that
escaped from the gallbladder (gallstone)
causes the jaundice. Whenever jaundice occurs, a doctor should be seen
immediately.
Other signs and symptoms of bile duct cancer include weight loss, loss
of appetite, and
fever. Early bile duct cancers usually do not cause pain. Usually the
main symptoms from intrahepatic bile duct cancer are weight loss and
fatigue. Jaundice occurs later. As the cancer
spreads, pain may develop in the stomach area.
If there is reason to suspect that you have bile duct cancer, your
doctor will perform certain exams and order tests to make a diagnosis.
If these tests indicate you do have bile duct cancer, additional tests
will be done to determine the stage of the cancer (how far the disease
has spread).
History and physical exam:
When your doctor "takes a history," he or she will ask you a series of
questions about your symptoms and risk factors. A physical exam for
patients suspected of having bile duct cancer will include a careful
exam of the abdomen to feel for masses or enlarged organs, and a
general survey of the rest of the body.
Blood chemistry and tumor
markers: Tests of the blood called blood chemistry tests
can very accurately determine if there is blockage of the bile duct. In
addition to a high level of bilirubin, the tests will find elevated
levels of another substance, called alkaline
phosphatase, which is released by damaged bile duct cells.
Although elevations of these substances indicate bile duct obstruction,
they cannot show if it is due to cancer or some other reason.
Tumor markers are substances produced by cancers and found in the
blood. The presence of these in high amounts usually means that there
is cancer, but the absence of these markers does not mean there is no
cancer, since not all cancers produce these markers. People with bile
duct cancer may have blood elevations of 2 markers -- carcinoembryonic antigen
(CEA) and CA 19-9.
For more information on these substances, please see the American
Cancer Society document, Tumor Markers.
Imaging Tests
Imaging techniques can often identify a bile duct blockage and the
blockage location. But they often do not reveal whether the blockage is
due to a tumor or a benign problem such as scarring.
Ultrasonography
(ultrasound): Ultrasound uses sound waves to produce
images of internal organs. A transducer emits sound waves and detects
the echoes as they bounce off the organs. The pattern of echoes is
processed by a computer to produce images. The echoes produced by most
tumors differ from those of normal tissue. These patterns of echoes can
help distinguish some types of benign and malignant tumors from one
another. Newer techniques, known as endoscopic
or laparoscopic ultrasound,
combine ultrasound with the use of a thin, lighted tube with an
attached viewing device (an endoscope
or laparoscope).
The endoscope is inserted through the mouth and passed through the
stomach and near the bile duct area. The laparoscope is inserted
through a surgical incision (cut) in the side of the patient's body.
Both procedures allow the doctor to place the ultrasound transducer
near the bile duct to produce more detailed images than a standard
ultrasound. If there is a tumor, the doctor may be able to tell if and
how far it has invaded, which helps in planning for surgery. Ultrasound
can often tell whether the cancer has invaded the liver. The ultrasound
may also be used to spot a tumor to biopsy.
Computed tomography (CT):
The CT scan is an x-ray procedure that produces detailed
cross-sectional images of your body. Instead of taking one picture,
like a conventional x-ray, a CT scanner takes many pictures as it
rotates around you. A computer then combines these pictures
into an image of a slice of your body. The machine will take multiple
pictures of the part of your body that is being studied.
CT scans are often used to make the initial diagnosis of bile duct
cancer and are helpful in determining the stage of the cancer
(determining the extent of its spread).
CT scans can also show the organs near the bile duct, as well as lymph
nodes and distant organs where the cancer may spread or metastasize. The CT
scan can help to determine whether surgery is a good treatment option.
This test can help tell whether your cancer has spread into your liver
or other organs. Often, after the first set of pictures is taken, you
will receive an intravenous (IV) injection of a "dye," or contrasting
agent that helps better outline structures in your body. A second set
of pictures is then taken.
CT scans can also be used to guide a biopsy needle precisely into a
suspected metastasis. For this procedure, called a CT-guided needle biopsy,
you remain on the CT scanning table, while a radiologist advances a
biopsy needle toward the location of the mass. CT scans are repeated
until the doctors are confident that the needle is within the mass. A fine-needle biopsy
sample (tiny fragment of tissue) or a core-needle biopsy
sample (a thin cylinder of tissue about ½-inch long and less than
1/8-inch in diameter) is removed and examined under a microscope.
CT scans are more tedious than regular x-rays because they take longer
and you need to lie still on a table while they are being done. But
just like other computerized devices, they are getting faster and your
stay might be pleasantly short. Also, you might feel a bit confined by
the ring you lie within when the pictures are being taken.
You will also need an IV line through which the contrast
"dye" is injected. The injection can also cause some flushing (redness
and warm feeling). Some people are allergic and get hives or, rarely,
more serious reactions like trouble breathing and low blood pressure.
Please be sure to tell the doctor if you have ever had a reaction to
any contrast material used for x-rays. You may be asked to drink 1 to 2
pints of a solution of contrast material. This helps outline the
intestine to allow for more accurate imaging of any tumor.
Magnetic resonance
imaging (MRI): MRI scans use radio waves and strong
magnets instead of x-rays. The energy from the radio waves is absorbed
and then released in a pattern formed by the type of tissue and by
certain diseases. A computer translates the pattern of radio waves
given off by the tissues into a very detailed image of parts of the
body. Not only does this produce cross-sectional slices of the body
like a CT scanner, but it can also produce slices that are parallel
with the length of your body. A contrast material might be injected
just as with CT scans, but is used less often. Some doctors believe
that MRI is the best way to look for bile duct cancer. This is
particularly true of a new method called MRI cholangiopancreatography.
This technique can often outline the exact site of bile duct blockage.
MRI scans are a little more involved than CT scans. First, they take
longer -- often up to an hour. Also, you have to be placed inside a
large tube, which is confining and can upset some people with claustrophobia (an
anxiety disorder that involves fear
of enclosed or confined spaces). The machine also makes a thumping
noise, but many
places will provide headphones with music to block this out.
Endoscopic retrograde
cholangiopancreatography (ERCP): In this procedure, a
doctor passes a long, flexible tube down the patient's throat, through
the esophagus and stomach, and into the common bile duct. The patient
is usually sedated so that the procedure is not uncomfortable. A small
amount of contrast medium (harmless dye) helps outline the bile duct
and pancreatic duct in x-ray images. The images can show narrowing or
blockage of the bile duct or pancreatic duct and the doctor can also
use the instrument to take cell samples. Sometimes doctors can find
cancer cells in the fluid in the duct.
Cholangioscopy:
This is a relatively new procedure that uses a very thin fiberoptic
tube. The tube can be passed into the bile duct through the mouth after
routine ERCP. It also can be passed through a needle placed into a
liver bile duct through the abdominal wall. From there it can be
maneuvered into the bile duct. This allows doctors to see any tumors
and even biopsy them.
Positron emission
tomography (PET): A PET scan uses glucose (a form of
sugar) that contains a radioactive atom. The substance emits tiny
subatomic particles called positrons. A special camera records the
precise location of the positrons as they leave the body. Cells of the
body absorb varying amounts of the radioactive sugar, depending on
their rate of metabolism. Unlike most other imaging tests, which
provide views of the shape and size of internal structures only, PET
scanning also provides information about their metabolic activity.
Since the metabolism of cancer cells differs from that of normal cells,
PET scanning can often tell if a bile duct obstruction is caused by a
cancer. It is also useful in determining how far the cancer may have
spread.
Cholangiography:
In this test, contrast dye is injected into the bile duct and x-ray
pictures are taken. A radiologist can inject the dye through a needle
that has been placed in a dilated
(opened) bile duct in the liver. This is usually done with ultrasound
guidance. A cholangiogram is a very important test in diagnosing bile
duct cancer because it can find the exact site of the cancer and show
how close it is to the liver. This helps doctors decide if the cancer
can be treated with surgery and how extensive the surgery will need to
be. If a cholangiogram cannot be done, an ERCP procedure can be
performed by a gastroenterologist (medical doctor specializing in
intestinal diseases).
Angiography:
For this test, a cannula
(small tube) is inserted into a blood vessel and maneuvered until it
reaches the area to be studied. Contrast dye is injected rapidly and a
series of x-ray images is then taken. When the pictures are complete,
the cannula is removed. Angiography is occasionally used to show
surgeons the location of blood vessels next to bile duct cancer, so
that the operation can be planned to minimize blood loss. Sometimes, if
there are too many blood vessels, the surgeons cannot remove the cancer
and surgery will not be done.
Other Tests
Laparoscopy:
This procedure uses a thin, lighted tube through which a doctor can
view the bile duct, gallbladder, the liver, and other internal organs,
and tissue in the area around the bile duct. The tube is inserted
through a small incision (cut) in the front of the abdomen. Laparoscopy
provides a view of organs that can help in planning surgery or other
treatments, and can help doctors confirm the stage (how far the tumor
has spread) of the cancer. Also, doctors can manipulate small
instruments through the laparoscopic incision(s) to remove small tissue
samples to examine under the microscope.
Biopsy:
Although imaging tests can suggest that a bile duct cancer is likely to
be present, a sample of bile duct cells or tissue must be examined
under a microscope to be sure of that diagnosis. CT scans can be used
to guide a biopsy needle precisely into a suspected tumor. For this
procedure, a CT-guided needle biopsy (described above) is done. Some
tissue is removed and examined under a microscope. This can also be done with cholangioscopy.
Bile duct cells and tiny fragments of bile duct tissue can also be
sampled by biliary
brushing. For this procedure, an endoscope is guided from
the mouth to the bile duct, as described earlier in the section on
cholangiography. Instead of injecting contrast dye and taking x-ray
pictures (as for ERCP), the doctor advances a small brush with a very
long, flexible handle through the endoscope. The end of the brush
(which resembles a tiny bottlebrush) is used to scrape cells and small
tissue fragments from the lining of the bile duct. As with a needle
biopsy, the cells and tissues are checked under a microscope for signs
of cancer. Last Revised: 04/17/2006
|
|
|
|
|
