Cancer of the Pancreas
About 95% of cancerous tumors of the pancreas are adenocarcinomas. Adenocarcinomas usually originate in the glandular cells lining the pancreatic duct. Most adenocarcinomas occur in the head of the pancreas, the part nearest the first segment of the small intestine (duodenum).
Adenocarcinoma of the pancreas has become increasingly common in the United States, occurring in about 10 of 100,000 people each year. Adenocarcinoma usually does not develop before age 50; the average age at diagnosis is 55. These tumors are nearly twice as common in men as in women and are slightly more common in blacks than in whites. Adenocarcinoma of the pancreas is 2 to 3 times more common in heavy smokers than in nonsmokers. People with chronic pancreatitis are at greater risk as well.
 See the sidebar Rare Types of Pancreatic Cancer.
Symptoms and Complications
Tumors in the head of the pancreas can interfere with the drainage of bile (the digestive fluid produced by the liver) into the small intestine (see Section 9, Chapter 124 and Section 10, Chapter 140). Therefore, jaundice (a yellowish discoloration of the skin and the whites of the eyes) caused by obstruction of bile flow is typically an early symptom. The jaundice is accompanied by itchiness all over the body resulting from the deposit of bile salt crystals under the skin. Vomiting may result from instances when cancer in the head of the pancreas obstructs the flow of stomach contents into the small intestine (gastric outlet obstruction) or obstructs the small intestine itself.
Adenocarcinoma of the body or tail of the pancreas (the middle part of the pancreas and the part farthest from the duodenum) typically causes no symptoms until the tumor has grown large. Thus, at the time of diagnosis, the tumor has already spread (metastasized) beyond the pancreas in 90% of the cases. It usually spreads to the neighboring lymph nodes, the liver, or the lung. Typically, the first symptoms are pain and weight loss. At the time of diagnosis, 90% of people have abdominal pain--usually severe pain in the upper abdomen that penetrates to the back--and significant weight loss.
Adenocarcinoma of the body or tail of the pancreas may obstruct the vein draining the spleen (the organ that produces, monitors, stores, and destroys blood cells), resulting in enlargement of the spleen (splenomegaly). Obstruction can also cause the veins to become swollen and twisted (varicose) around the esophagus (esophageal varices) and stomach. Severe bleeding may result, particularly from the esophagus, if these varicose veins rupture.
Diagnosis
Early diagnosis of tumors in the body or tail of the pancreas is difficult because symptoms occur late and physical examination and blood test results are often normal. When adenocarcinoma of the pancreas is suspected, the most accurate diagnostic test is computed tomography (CT). Other commonly used tests are ultrasound scans, endoscopic retrograde cholangiopancreatography (see Section 10, Chapter 134 and Section 10, Chapter 134), and magnetic resonance imaging (MRI).
To confirm the diagnosis, a doctor may obtain a sample of the pancreas for examination under a microscope (biopsy) by inserting a needle through the skin using a CT or ultrasound scan as a guide. However, this approach often misses the tumor and may spread cancer cells out of the local area along the track of the needle. The same approach may be used to obtain a biopsy sample from the liver to look for cancer that has spread to the pancreas. If the results of these tests are normal but the doctor still strongly suspects adenocarcinoma, the pancreas may be evaluated surgically.
Prognosis and Treatment
Because adenocarcinoma of the pancreas has usually spread to other parts of the body before it is discovered, the prognosis is very poor. Fewer than 2% of people with adenocarcinoma of the pancreas survive for 5 years after the diagnosis. The only hope of a cure is surgery, which is performed on about 10% of people in whom it is believed that the cancer has not spread. Either the pancreas alone or the pancreas and the duodenum are removed. After such surgery, only 15 to 20% of people live for 5 years. Additional chemotherapy and radiation therapy are not likely to improve survival time or rates substantially.
Mild pain may be relieved by aspirin or acetaminophen. Most often, stronger painkillers, such as oral codeine or morphine, are needed. For 70 to 80% of people with severe pain, injections into nerves to block pain sensations may provide relief. The lack of pancreatic digestive enzymes can be treated with oral enzyme preparations. If diabetes develops, insulin treatment may be needed.
Obstruction of bile flow may be temporarily relieved by placement of a tube (stent) in the lower portion of the duct that drains bile from the liver and gallbladder. In most cases, however, the tumor eventually obstructs the duct above and below the stent. An alternative treatment method is the surgical creation of a channel that bypasses the obstruction. For example, an obstruction of the small intestine can be bypassed by a channel that connects the stomach with a portion of the small intestine that is beyond the obstruction.
Because adenocarcinoma of the pancreas is fatal in most cases, a doctor usually discusses end-of-life care with the person, family members, and other health care practitioners (see Section 1, Chapter 8).
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