Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Pancreatic Cancer

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States. It occurs primarily in the head of the organ and progresses to death within a year of diagnosis. Rarer tumors are those of the body and tail of the pancreas and islet cell tumors.

Age Alert

The incidence of pancreatic cancer increases with age, peaking between ages 60 and 70.

Causes

·   Inhalation or absorption of carcinogens, which are excreted by the pancreas

§  Cigarette smoke

§  Food additives

§  Industrial chemicals, such as beta-naphthalene, benzidine, and urea

Predisposing factors

·   Chronic pancreatitis (may be early manifestation of disease)

·   Diabetes mellitus (may be early manifestation of disease)

·   Chronic alcohol abuse

Pathophysiology

Most pancreatic tumors are adenocarcinomas that arise in the head of the pancreas. The two main tissue types are cylinder-cell and large, fatty, granular-cell tumors. Cancers of the pancreas progress insidiously and most have metastasized before diagnosis. Cancer cells may invade the stomach, duodenum, major blood vessels, bile duct, colon, spleen, and kidney, as well as the lymph nodes.

Signs and symptoms

·   Weight loss, anorexia, fatigue

·   Pruritus, skin lesions (usually on the legs)

·   Abdominal or low back pain

·   Jaundice

·   Diarrhea

·   Fever

·   Hyperglycemia, glucose intolerance

·   Recurrent thrombophlebitis

·   Clay-colored stools

Diagnostic test results

·   Laparotomy with biopsy confirms cell type.

·   Ultrasound identifies location of mass.

·   Angiography reveals vascular supply of the tumor.

·   Endoscopic retrograde cholangiopancreatography visualizes tumor area.

·   Computed tomography scan and magnetic resonance imaging identify tumor location and size.

·   Serum laboratory tests reveal increased serum bilirubin, serum amylase, and serum lipase.

·   Prothrombin time is prolonged.

·   Elevations of aspartate aminotransferase and alanine aminotransferase indicate necrosis of liver cells.

·   Marked elevation of alkaline phosphatase indicates biliary obstruction.

·   Plasma insulin immunoassay shows measurable serum insulin in the presence of islet cell tumors.

·   Hemoglobin and hematocrit levels may show mild anemia.

·   Fasting blood glucose reveals hypoglycemia or hyperglycemia.

Treatment

·   Seldom successful because disease is usually metastatic at diagnosis

·   Surgery including total pancreatectomy, cholecystojejunostomy, choledochoduodenostomy, choledochojejunostomy, pancreatoduodenectomy or Whipple's procedure, gastrojejunostomy

·   Placement of a biliary stent

·   Possibly, radiation therapy and chemotherapy

·   Analgesics

·   Antibiotics

·   Anticholinergics

·   Antacids

·   Diuretics

·   Insulin

·   Pancreatic enzymes

P.201

PANCREATIC ADENOCARCINOMA

image