PANCREATIC CANCER
4th leading cause of cancer deaths in G and E. 25,000 cases/yr in the U.S. and nearly that # of deaths. Vast majority of pts present w/unresectable disease & 5 yr survival is ~ 5%.
Cause of tumor is unknown. Risk factors include smoking & chronic pancreatitis.
1/2 of pancreatic Ca arise in the head, 1/2 in the body and tail.
Distal common bile duct runs through pancreatic head. Pancreatic Ca most often occur in this area making this tumor the most commonly associated w/malignant biliary obstruction.
Courvoisier' s law: Obstructing malignancies of the distal CBD produce a palpable non-tender gallbladder. Why? Because common duct stones (the main DDx) are usually associated w/chronic cholecystitis à contracted gallbladder.
Pancreatic Adenocarcinoma
Clinical manifestations depend on location where the tumor arises. Does not announce its presence unless bile duct is obstructed.
1. Arising in the head: tend to obstruct the common bile duct, causing jaundice or distended, non-tender gall bladder. May be able to palpate bile duct in thin patient.
2. Otherwise non-specific: weight loss and pain (due to neural invasion of the tumor).
3. Laboratory tests are not specific.
Imaging studies:
Endoscopic US
MRI
Dilated bile duct & pancreatic duct may suggest mass in pancreas.
CEA and CA 19-9 tend to be
Although US and radiologic imaging have diagnostic accuracy, it is not easy to make diagnosis in an early stage. Because of the difficulty of diagnosis, only 10-15% are candidates for surgery.
Treatment:
Surgical resection: Potentially "curative" surgery is only possible in 10-15% of pts who present w/early tumors à jaundice due to bile duct obstruction.
1. Whipple's procedure: proximal pancreatectomy, duodenectomy, partial gastrectomy and gastrojejunostomy.
2. Palliation: biliary bypass, chemotherapy, radiation.
Prognosis: Dismal. 5 year survival is approximately 5%. 5-year survival of patients who under surgical resection for cure is only 10%. The mean survival for patients with surgically unresectable tumors is 5 months. Palliative treatment is aimed at relieving biliary obstruction and treating pain.
Pancreatic Islet Cell Tumors
Tumors arising in endocrine portion of the pancreas are rare compared to adenocarcinomas. They can be benign or malignant, and functional (release hormones) or non-functional. Distinct clinical syndromes associated with hyperfunctioning islet cells include insulinoma, gastrinoma (Zollinger-Ellison syndrome), glucagonoma, and somatostatinoma
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