Health Questions and Answers

Pancreatic Cancer

What are the most common histologic forms of malignant tumors of the pancreas?
Almost 90% of pancreatic cancers are moderately well-differentiated adenocarcinomas, derived from the pancreatic ductal epithelium. About 5% of pancreatic cancers originate from the pancreatic islet cells. Other rare types of pancreatic cancer include sarcomas, lymphomas, and cystadenocarcinomas.

Define intraductal papillary-mucinous tumors of the pancreas.
Intraductal papillary-mucinous tumors (IPMT) of the pancreas (also called mucinous ductal ectasia, mucin-producing tumors, ductectatic mucinous cystadenomas, intraductal cystadenomas, intraductal papillary tumors) are characterized by intraductal papillary growth and production of mucin. These tumors usually grow slowly and cause dilatation of the main pancreatic duct and its branches with potential development of cellular hyperplasia, atypia, and malignancy.

What is the most common location of the pancreatic adenocarcinoma?
Eighty percent of pancreatic adenocarcinomas are located in the head of the pancreas. This location may lead to obstruction of the distal common bile duct with development of obstructive jaundice.

What is Courvoisier’s sign?
A palpable, distended gallbladder in the right upper quadrant in a patient with jaundice is called Courvoisier’s sign. Usually, it results from a malignant bile duct obstruction, such as pancreatic cancer with complete obstruction of the distal common bile duct and accumulation of bile in the gallbladder. This finding is not specific for pancreatic cancer. Patients with distal cholangiocarcinoma or an ampullary mass may also present with Courvoisier’s sign.

What is the survival rate for patients with pancreatic cancer?
Less than 20% of patients with pancreatic cancer are alive 1 year after diagnosis, and less than 3% survive longer than 5 years. Surgical resection of the tumor is the only curative treatment. At the time of diagnosis, 40% of patients already have locally advanced disease, and more than 40% have visceral metastasis. The stage of the disease at presentation and the surgeon’s ability to remove the tumor completely are the most important determinants of treatment outcome and long-term survival.

What are the risk factors for development of pancreatic cancer?
Smokers are twice as likely to develop pancreatic cancer as nonsmokers. Pancreatic cancer is more common in countries where the diet contains a large amount of fat and meat products. In contrast, high intake of dietary fiber appears to be protective. Extensive studies have failed to prove a definitive link between coffee intake and development of pancreatic cancer. Recent studies indicated that diabetes mellitus (especially recent onset of diabetes in an older patient) may be a risk factor. Chronic pancreatitis increases the risk. Some patients may have a genetic (familial) predisposition. Patients with pernicious anemia, and patients who have undergone partial gastrectomy, have an elevated risk. Predisposing environmental hazards include oil refining, paper manufacturing, and chemical manufacturing.

What is the estimated risk for pancreatic cancer among persons with hereditary pancreatitis (HP)?
Hereditary pancreatitis is an autosomal dominant trait with high phenotypic penetrance. International study groups have calculated a 50- to 70-fold increased risk of pancreatic cancer among patients with HP, with a 40% cumulative risk at age 70. Ideally, screening for pancreatic cancer should be offered to patients of ages 35-40. Optimally, screening should be conducted at expert medical centers with state-of-the-art imaging in conjunction with standardized collection of blood/serum and pancreatic juice for scientific study.

Is alcohol consumption an important risk factor for development of pancreatic cancer?
Many epidemiologic studies in Europe and the United States have failed to find a consistent, direct association between alcohol intake and development of pancreatic cancer.

What are the most common symptoms in patients with pancreatic cancer?
Patients with pancreatic cancer present usually with abdominal pain, radiating frequently to the back; weight loss; nausea; anorexia; generalized weakness; and easy fatigability. Obstructive jaundice may develop early in the disease in patients with a mass in the head of the pancreas. Jaundice may never develop or develop late in patients with a tumor in the body or tail of the pancreas; in such patients, jaundice indicates the presence of liver metastases.

What imaging modalities are used to diagnose pancreatic cancer?
Transabdominal ultrasound is usually the first diagnostic test. Its sensitivity in the detection of pancreatic tumors is around 70%. CT and MRI are more sensitive than transabdominal ultrasound, especially for detection of regional and distal metastases. Endoscopic ultrasonography is the most accurate (sensitivity: 77-100%) diagnostic modality to detect small tumors and to evaluate the local spread of tumor into surrounding organs and blood vessels. Endoscopic retrograde cholangiopancreatography (ERCP) is sensitive (78-95%) and specific (88-95%) for pancreatic cancer and is frequently used to perform palliative drainage of the biliary ducts.
KEY POINTS: PANCREATIC CANCER

  1. Most patients with pancreatic carcinoma develop symptoms late in the course of the disease.
  2. The lack of early warning symptoms leads to a delay in diagnosis, and less than 20% of patients present with resectable disease.

What is the “double-duct sign” in patients with pancreatic cancer?
The double-duct sign, noted on ERCP, demonstrates the presence of stenosis of the common bile duct and pancreatic duct in the head of the pancreas. In patients with obstructive jaundice or a pancreatic mass, the double-duct sign has a specificity of 85% in predicting pancreatic cancer.

Can serum markers diagnose pancreatic cancer?
Many potential serum markers are currently under evaluation to facilitate the early detection of pancreatic cancer. The carbohydrate antigen CA19-9 is highly sensitive (>90%) in diagnosing pancreatic cancer but has low specificity (75%) and is often normal in early stages of the disease (tumor <1 cm in diameter). Many conditions can lead to elevation of CA19-9: chronic pancreatitis, biliary diseases, and other types of gastrointestinal (GI) cancer. After complete resection of pancreatic cancer, the serum level of CA19-9 usually falls. Persistently elevated serum levels of CA19-9 after surgery may indicate inadequate resection or metastatic lesions. Recurrence of pancreatic cancer can manifest with elevation of CA19-9 levels following a decline after surgical resection.

What are the common biochemical abnormalities in patients with pancreatic cancer?
Patients with biliary tract obstruction can present with elevated serum bilirubin and alkaline phosphatase (obstructive pattern). Serum amylase is elevated in only 5% of patients.

Is chemotherapy effective for patients with advanced pancreatic cancer?
Traditional chemotherapy with 5-fluorouracil has an overall response rate below 10%, with no effect on quality of life or survival. Gemcitabine, which in one study demonstrated improvement in disease-related symptoms and survival in advanced pancreatic cancer, is now under clinical evaluation as a single agent and in combination with 5-fluorouracil and cisplatin.

What is the median survival after the diagnosis of advanced pancreatic cancer?
Pancreatic cancer has the poorest prognosis among other GI tumors. It is the fifth leading cause of death in the United States. The median survival of patients with advanced pancreatic carcinoma is approximately 4 months.

What is a Whipple’s resection?
Whipple’s resection (pancreaticoduodenectomy) is the most common surgical procedure for resectable cancer located in the head of the pancreas. It involves a partial gastrectomy (resection of the antrum), cholecystectomy, and removal of the distal common bile duct, duodenum, head of the pancreas, proximal jejunum and regional lymphatic nodes. The procedure includes usually pancreaticojejunostomy, hepaticojejunostomy, and gastrojejunostomy.

Describe the role of celiac blockade in patients with pancreatic cancer.
Celiac blockade (chemical splanchnicectomy) is injection of 50% alcohol on each side of the aorta at the level of celiac axis. This procedure has been shown, prospectively, to improve preexisting pain significantly and to delay onset of pain in asymptomatic patients. Celiac blockade can be done at laparotomy, under radiologic guidance, or at the time of endoscopic ultrasound.

What surgical procedures are used for cancer in the body and tail of the pancreas?
Surgical resection consists usually of distal pancreatectomy and splenectomy. This operation is technically easier than Whipple’s procedure.

When do patients with pancreatic cancer need palliative procedures?
Patients with unresectable cancer in the head of the pancreas can develop obstructive jaundice, pruritus, or cholangitis. These conditions can be palliated by endoscopic placement of plastic or self-expending metal stents (Wallstent). If endoscopic stent placement is not possible, transhepatic transcutaneous stents can be inserted by an interventional radiologist. When placement of stents by an endoscopist or radiologist fails, bypass surgical procedure (cholecystojejunostomy or hepaticojejunostomy) may be indicated. In patients with duodenal obstruction by a large pancreatic mass, endoscopy with palliative placement of an expandable stent into the duodenum is indicated to relieve the obstruction. If endoscopy is not possible, surgical bypass procedure (gastrojejunostomy) may be performed.

References

WEBSITES
http://www.path.jhu.edu/pancreas
http://www.dave1.mgh.harvard.edu
http://www.vhjoe.com

BIBLIOGRAPHY

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