The incidence of cancer of the pancreas has increased steadily over the past 25 years. In males it is the fourth commonest cancer causing death, exceeded only by cancers of the lung, colon and rectum, and prostate. In females it is the fifth commonest cause of death, with only cancers of the breast, colorectum, lung, and ovary/uterus being more frequent. The incidence is higher in males, with a sex ratio of two males to each female; peak incidence occurs in the fifth through seventh decade.

The overall five-year survival rate is less than 3%, and most patients who develop carcinoma of the pancreas die within six months of diagnosis. The poor prognosis in this condition is secondary to the inability to diagnose the carcinoma at an early stage. When symptoms present, the tumor is far advanced and often has metastasized to regional lymph nodes and to adjacent and distant organs, as shown in Table 7.

Ductal cell adenocarcinoma accounts for 90% of pancreatic tumors. Approximately 5% of pancreatic carcinomas are of islet cell origin; the rest consist of cystadenocarcinoma, giant cell carcinoma and epidermoid carcinoma. The head of the pancreas is the commonest site of involvement, accounting for 70% of the cases, whereas the body and tail account for 20% and 10% of the cases, respectively.

Several etiological agents have been invoked in the pathogenesis of pancreatic carcinoma, although most of the studies have not yielded consistent results. Epidemiologically, long-term cigarette smoking is a well-established risk factor. The mechanism causing carcinoma is not proven and has been explained on the basis of the presence of a carcinogen in tobacco smoke. High-fat or high-protein diets tend to stimulate CCK release from the duodenum, which in turn can cause pancreatic hypertrophy and may predispose to carcinoma, although the evidence is not convincing. Diabetics are at twice the risk of developing carcinoma of pancreas as the general population. The mechanism of this is not known. There is no evidence to suggest that alcoholic chronic pancreatitis predisposes to carcinoma. A recent study has shown a four- to five-fold increase in pancreatic carcinoma in individuals exposed to DDT (dichlorodiphenyltrichloroethane).

Some epidemiological studies have suggested an increased rate of pancreatic carcinoma in patients who drank chlorinated water; this remains to be proven. Genetic defects have also been invoked, such as oncogenes and 53 p tumor suppressor mutation, in addition to some evidence suggesting an increase in epidermal growth factor receptor activity.

The major symptoms of pancreatic carcinoma include pain, jaundice and weight loss.

Rapid and progressive weight loss is probably the commonest symptom of carcinoma of the pancreas, and is not related to the location or the extent of the tumor.

Most (up to 90%) of the patients suffer from pain during the course of the disease. The pain frequently is a dull aching or boring. Located in the epigastrium, it radiates to the back and increases in severity at night. Depending on the site of the tumor, the pain may radiate to the right or left upper quadrant. Unrelenting pain results from retroperitoneal extension, with invasion of the neural plexuses around the celiac axis.

Jaundice may be the presenting symptom in up to 30% of the patients, and the incidence increases as the disease progresses. It may be associated with pain and pruritus. Jaundice is more common when the head of the pancreas is involved, but obstruction or jaundice can occur secondary to spread to the liver or to lymph nodes around the bile duct. Other nonspecific symptoms include bloating, nausea and vomiting, weakness and fatigue, and diarrhea.

The commonest finding in carcinoma of the head of the pancreas is jaundice, with abdominal tenderness and an enlarged liver. Less common signs include a palpable gallbladder, an abdominal mass and edema. Thrombophlebitis occurs in less than 10% of the patients.

The development of diabetes in a middle-aged man or elderly patient with no family history of diabetes should suggest pancreatic carcinoma, especially when this is associated with abdominal pain or weight loss.

Laboratory tests are often normal or nonspecific. Serum alkaline phosphatase and bilirubin are evaluated when the bile duct is obstructed or there are hepatic metastases. Serum amylase may be moderately elevated but also may be normal. Pancreatic secretory studies are not often helpful, since findings overlap with chronic pancreatitis.

Several tumor markers have been detected in the sera of patients with pancreatic carcinoma. These include pancreatic oncofetal antigen (POA), a-fetoprotein (AFP), carcinoembryonic antigen (CEA), and pancreatic cancer associated antigen. Certain serum tumor markers such as CA 19-9 and CA 242 have been useful in following the progression of pancreatic cancer but not in its diagnosis. These tests are nonspecific and not sensitive enough for screening purposes. Cytologic specimens can be obtained by percutaneous needle aspiration under ultrasound or CT guidance and by aspiration of duodenal or pancreatic juices at ERCP. Positive cytology may guide further management; on the other hand, negative cytology does not rule out the disease.

Ultrasonography is the procedure of choice for detecting pancreatic cancer. Its usefulness is dependent on the examiner's expertise (Figure 8). Examination may be less than optimal in the presence of increased bowel gas. The sensitivity of this test in pancreatic cancer is reported to be 76-94%, with a specificity of 96%. Once a lesion is detected, a guided biopsy may be helpful in establishing the diagnosis. When obstructive jaundice is present, ultrasound may reveal the presence of hepatic lesions or obstruction of the biliary tree. This procedure is simple and involves no radiation exposure.

Computerized tomography (CT) is more accurate and gives more information than ultrasonography (Figure 9). However, it is also more expensive and involves low radiation exposure; also, small centers may not have the equipment. With this technique, bowel gas does not interfere with the visualization of the pancreas. There is better identification of any retroperitoneal invasion. A guided biopsy of the lesion is also possible. However, small early lesions (especially in the head of the pancreas) may be missed on CT scan; hence, its usefulness in early diagnosis is not clear.

When there is a clinical suspicion of a pancreatic lesion and the ultrasound or CT scan is normal, an ERCP is helpful. It has the advantage of combining gastroduodenoscopy, cholangiography and pancreatography. The papilla may also be examined and cytologic sampling may be obtained. When obstruction is present, therapeutic drainage via stents may be attempted. Angiography is no longer used for diagnosing pancreatic carcinoma, but is still useful to evaluate patients who have known carcinoma for resectability, outlining vascular anatomy. Newer diagnostic tools such as endoscopic ultrasound may further improve selection of patients who might benefit from curative surgery. Magnetic resonance imaging has no apparent advantage over CT.

At the time of presentation, 75%-80% of patients have an unresectable tumor. Pancreatectomy or pancreatoduodenal resection for localized disease is the only treatment that carries a potential for cure. Despite this intervention, the disease carries a poor long-term prognosis, with a survival rate of 3% at five years. Factors that lead to a poor prognosis in pancreatic carcinomas include the presence of tumor in the lymph nodes, vascular invasion, tumor size greater than 2.5 cm and histologically poorly differentiated tumor. Complications can occur in up to 20% of patients following pancreaticoduodenectomy. These include delayed gastric emptying, pancreaticojejunal leak, intra-abdominal sepsis, biliary anastomotic leak, gastrointestinal bleeding and other intra-abdominal hemorrhage. Factors favoring longer survival include jaundice at presentation, a small tumor mass, early tumor stage and a well-differentiated tumor. Palliative operations for unresectable tumor offer some relief, such as alleviating biliary or duodenal obstruction. Operative intervention is frequently associated with high morbidity and mortality; hence, nonsurgical intervention may be preferable. Biliary obstruction can be relieved by percutaneous drainage or by endoscopic stenting of the bile duct. Unfortunately these stents tend to occlude and may require frequent changes.

Adjuvant chemotherapy has not been demonstrated to be beneficial in long-term survival. Irradiation therapy has been advocated in treating larger tumors; it may offer local control and pain management, although its benefit in long-term survival has not been proven.