The Pancreas & Pancreatic Cancer
About the Pancreas | What Is Cancer? | Pancreatic Cancer
What Are The Symptoms? | Methods of Diagnosis | Treatment & Surgery | Risk Factors
About the Pancreas
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.
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 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 Pacreatic 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. 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.
What Are The Symptoms?
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).
Methods of Diagnosis
Patients who have symptoms of unexplained weight loss, continuous diarrhea, new abdominal mid-back pain, or new onset of adult diabetes should visit a doctor, who will obtain more information about the person, perform a physical exam, and perhaps order laboratory tests. If a disease of the pancreas is suspected, the doctor usually orders procedures that can produce pictures of the pancreas. 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 are as follows:
- CT scans are 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. CT scanning are best for detecting cancers that are larger or equal to 2cm in size (approximately one inch).
- Endoscopic ultrasonography (EUS) uses high-frequency sound waves 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 on the end of it. The ultrasound probe is placed into the stomach and the small intestine adjacent to the pancreas. The physician can evaluate the ultrasound 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 small tissue sample using a needle guided into the tumor.
- Endoscopic retrograde cholangiopancreatography (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 main pancreatic duct 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. Occasionally it is not possible to obtain a sample of a suspected cancer.
- 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.
Treatment & Surgery
Options for management of pancreatic adenocarcinoma usually involve combinations of surgery, chemotherapy, and radiation that must be customized for individual patients, based on patient factors and the location and extent of the cancer. Of these three types of treatment, only surgery offers the potential for cure and then only in a carefully selected subset of patients. Patients who may be cured with surgery (supported by other, adjunctive therapy) are those with localized disease that can be completely removed to clear margins. Unfortunately for many patients, by the time the cancer is detected it has escaped the local region of the pancreas and spread into adjacent organs or regional lymph node beds, and/or systemically to the liver, lungs, and beyond. In such patients, surgery may still be considered to improve the quality of a patient’s life by controlling complications of the disease such as bleeding, bile duct, or intestinal obstruction.