The pancreas is an organ deep within the body.
It is located in the abdomen, right in front of the spine. In front of
the pancreas is the stomach, and on either side is the beginning of the
small bowel and the spleen. [Figure 1]
The pancreas has two main jobs: one is to maintain even levels of
blood sugar by secreting insulin; the other job is to make and deliver
the enzymes that help digest food. These enzymes are made in the
pancreas and delivered into the small intestine where the food is
digested. People can live without a pancreas, although they would not be
able to control their blood sugars (diabetes) and would require insulin
injections and enzyme tablets to help digest the food.
Figure 1. The pancreas it is located in the abdomen, in front of
the spine, where it can not be felt from outside the body.
What is Cancer?
Normally, cells grow and divide to produce more cells only when the
body needs them. This orderly process keeps the body healthy. Sometimes
cells keep dividing when new cells are not needed, forming a mass of
extra tissue called a growth or a tumor. Tumors can be malignant or
benign. Malignant tumors, or cancer, occur when cells divide without
order and invade and destroy the tissue around them. Benign tumors occur
when cells divide abnormally, but there is no spread into other tissues.
- Benign tumors are not cancer and usually do not threaten life.
They often can be removed, and they usually do not come back. Cells in
benign tumors do not spread to other parts of the body (e.g. they do
not metastasize). There are many types of benign tumors of the
pancreas and in general they are relatively uncommon tumors.
- Malignant tumors are cancer. Cancer cells divide without control,
invading and destroying the tissue around them. Also, cancer cells can
break away from a malignant tumor and enter the blood or lymph system.
This process, called metastasis, is the way that cancer spreads to
other parts of the body. There are different types of cancer that can
occur in the pancreas, but the most common type of cancer begins in
the ducts that carry pancreatic digestive juices to the small bowel.
Because the cancer starts in the pancreatic ducts, we refer to it as
ductal adenocarcinoma. This is the type of cancer most people think
about when talking about pancreatic cancer.
How does pancreatic cancer grow?
Pancreatic cancer starts out in the pancreatic ducts. Pancreatic
ducts are a set of tube-like structures that help the pancreatic enzymes
to reach the small intestine-- so that food can be digested. [Figure] As
pancreatic cancer grows, the tumor may invade organs that surround the
pancreas, such as the stomach or small intestine. Pancreatic cancer
cells may also break away from the tumor and spread to other parts of
the body. When pancreatic cancer cells spread, they often form new
tumors in lymph nodes and the liver, and sometimes in the lungs or
bones. The new tumors have the same kind of abnormal cells and the same
name as the original (primary) tumor in the pancreas. For example, if
pancreatic cancer spreads to the liver, the cancer cells in the liver
are pancreatic cancer cells. The disease is metastatic pancreatic
cancer; it is not liver cancer.
Figure 2. The pancreas makes insulin to control blood sugar and
enzymes to help digest food. The liquid enzymes travel through the ducts
and are squirted into the small intestine that help digest food.
What are the symptoms of pancreatic cancer?
Many patients who have pancreatic cancer have no symptoms or very
vague symptoms until the cancer is fairly large. This because the
pancreas is so deep in the body that symptoms don't develop until it
gets big enough to cause problems. Thus, the location of the cancer in
the pancreas and/or the size of the tumor can lead to a variety of
symptoms. If the tumor blocks the common bile duct, so that bile cannot
pass from the gallbladder into the intestines, the bile then backs up
into the bloodstream. The skin and whites of the eyes can become yellow,
and the urine may become dark. This condition is called jaundice.
Another common symptom is pain; it may be caused by a blockage of the
main pancreatic duct (becoming worse after the person eats) or because
the cancer is getting into the nerves that supply the pancreas and
abdomen. Cancer of the pancreas can also cause nausea, loss of appetite,
diarrhea, weight loss, and/or diabetes (loss of blood sugar control).
Diagnosis
Patient's with symptoms should visit a doctor, who will more
information about the person, perform a physical exam, and perhaps order
to laboratory tests. The doctor usually orders procedures that produce
pictures of the pancreas and the area around it. Pictures or images can
help the doctor diagnose cancer of the pancreas and understand whether
it has spread or not. By fully understanding the location and extent of
the cancer, doctors can decide how to treat it.
Methods of obtaining pictures or images of the pancreas and it's
surrounding organs:
- CT scanning, is very commonly used to evaluate the pancreas and
the rest of the abdomen. A CT scanner is an x-ray machine linked with
a computer. The machine takes x-rays as the patient lies on a bed in
the machine and the computer puts the x-rays together to produce
detailed pictures. If a suspicious tumor is seen at CT scan, it may be
possible for the doctor to obtain a sample of the tumor by using a
long needle that is guided by the CT scanner.
- ndoscopic ultrasonography (EUS) uses of high-frequency sound
waves, that cannot be heard, to make images of the pancreas. To make
these EUS images, a patient lies on a bed, is sedated, and swallows a
flexible tube with an ultrasound probe of the end of it. The probe is
placed into the stomach and the small intestine, adjacent to the
pancreas. The physician can evaluate the images and take photographs
if needed. The procedure usually takes about 30-40 minutes and can
give a very sensitive and detailed look at the pancreas. If a tumor is
present, it may be possible during the procedure to get a very small
sample of it using a needle guided into the tumor.
- ERCP is a method for taking x-rays of the pancreatic ducts and
bile ducts that hook up to the main pancreatic duct. The patient lies
down on a bed and is made very sleepy; a long, flexible tube
(endoscope) is passed through the mouth down into the stomach, and
then into the small intestine. The doctor then injects contrast
solution into the ducts and takes x-rays. This is another very
sensitive test for evaluating the pancreas. It is also possible during
this test to get a very small sample of tumors, or abnormal looking
ducts, using a tiny brush.
- Magnetic Resonance Imaging (MRI) is a powerful magnet linked to a
computer. The MRI machine is very large, with space for the patient to
lie in a tunnel inside the magnet. The machine measures the body's
response to the magnetic field, and the computer uses this information
to make detailed pictures of areas inside the body. The information
gained is similar to the information gained at ERCP, except that it is
not quite as sensitive in picking up very small changes. Samples of
the tumor can not be obtained at this procedure.
Other tests besides the ones listed above may be used together or in
place of the tests listed. Physicians will try to make the patient as
comfortable as possible, while the tests are being performed. Pictures
of the pancreas and nearby organs provide important clues as to whether
a person has cancer. However, getting a sample of the tumor or
suspicious area is the only sure way for the doctor to learn whether
pancreatic cancer is present. Samples can be obtained using a needle (CT
and EUS) or by using a brush (ERCP) or at surgery [see surgical biopsies
below]. The larger the sample of tissue the easier it is for the
pathologist to make an accurate diagnosis. A pathologist looks at the
tissue under a microscope, whether it is from a needle, brush, or
surgical biopsy, to check for cancer cells.
Biopsies can be obtained at surgery using one of two techniques. In
one type of surgery, called laparoscopy the doctor inserts a lighted
flexible tube into the abdomen through a couple of one inch incisions.
In addition to removing tissue samples to be examined under the
microscope, the doctor can see inside the abdomen to determine the
location and extent of the disease. During laparoscopy, the doctor can
decide whether a larger operation is needed to remove the tumor or to
relieve symptoms caused by the cancer. This type of operation is
relatively easy on the patient because they heal up quickly.
In some cases, a laparotomy is necessary to make a diagnosis. In this
operation, the doctor makes a large incision (6-10 inches) and directly
examines the organs in the abdomen. If cancer is found, the doctor can
go ahead with further surgery. (The types of surgery done to treat
pancreatic cancer are described in the "Treatment Methods" section.)
