Pancreatic cancer
Pancreatic cancer: Excerpt from Professional Guide to Diseases (Eighth Edition)
A deadly GI cancer, pancreatic cancer progresses rapidly. Most pancreatic tumors are adenocarcinomas and arise in the head of the pancreas. Rarer tumors are those of the body and tail of the pancreas and islet cell tumors. The two main tissue types are cylinder cell and large, fatty, granular cell.
Causes and incidence
Evidence suggests that pancreatic cancer is linked to inhalation or absorption of the following carcinogens, which are then excreted by the pancreas:
❑cigarettes
❑food additives
❑industrial chemicals, such as beta-naphthalene, benzidine, and urea.
Possible predisposing factors are chronic pancreatitis, diabetes mellitus, and chronic alcohol abuse (both pancreatitis and diabetes mellitus may be early manifestations of the disease as well).
Pancreatic cancer incidence increases with age, peaking between ages 60 and 70. Geographically, the incidence is highest in Israel, the United States, Sweden, and Canada.
Signs and symptoms
The most common features of pancreatic cancer are weight loss, abdominal or low back pain, jaundice, and diarrhea. Other generalized effects include fever, skin lesions (usually on the legs), and fatigue. (See Types of pancreatic cancer, page 88.)
Diagnosis
Definitive diagnosis requires a laparotomy with a biopsy.
Other tests used to detect pancreatic cancer include:
❑ultrasound of the abdomen — can identify a mass but not its histology
❑computed tomography scan of the abdomen — similar to ultrasound but shows greater detail
❑ angiography — shows vascular supply of tumor
❑ endoscopic retrograde cholangiopancreatography — allows visualization, instillation of contrast medium, and specimen biopsy
❑ magnetic resonance imaging of the abdomen — shows tumor size and location in great detail.
Laboratory tests supporting this diagnosis include serum bilirubin (increased); serum amylase and serum lipase (sometimes elevated); prothrombin time (prolonged); aspartate aminotransferase and alanine aminotransferase (elevations indicate necrosis of liver cells); alkaline phosphatase (marked elevation occurs with biliary obstruction); plasma insulin immunoassay (shows measurable serum insulin in the presence of islet cell tumors) (see Islet cell tumors); hemoglobin (Hb) and hematocrit (HCT) (may show mild anemia); fasting blood glucose (may indicate hypoglycemia or hyperglycemia); and stools (occult blood may signal ulceration in GI tract or ampulla of Vater).
Treatment
Treatment of pancreatic cancer is rarely successful because this disease has usually metastasized widely at diagnosis. Therapy consists of surgery and, possibly, radiation and chemotherapy. Standard chemotherapy for patients with locally unresectable cancer includes gemcitabine. Gemcitabine has been demonstrated to improve the quality of life through better pain control, adequate performance status, decreased analgesic consumption, shrinkage of tumor, and prolonged survival. (See Staging pancreatic cancer, page 90.)
Other medications used in pancreatic cancer include:
❑antacids (by mouth or by nasogastric [NG] tube) — to decrease secretion of pancreatic enzymes and to suppress peptic activity, thereby reducing stress-induced damage to gastric mucosa
❑ antibiotics (oral, I.V., or I.M.) — to prevent infection and relieve symptoms
❑ anticholinergics (particularly propantheline) — to decrease GI tract spasm and motility and reduce pain and secretions
❑ diuretics — to mobilize extracellular fluid from ascites
❑ insulin — to provide adequate exogenous insulin after pancreatic resection
❑ opioids — to relieve pain, but only after analgesics fail because morphine, meperidine, and codeine can lead to biliary tract spasm and increase common bile duct pressure
❑ pancreatic enzymes (average dose 0.5 to 1 mg with meals) — to assist in digestion of proteins, carbohydrates, and fats when pancreatic juices are insufficient because of surgery or obstruction.
Small advances have been made in the survival rate with surgery:
❑ Total pancreatectomy may increase survival time by resecting a localized tumor or by controlling postoperative gastric ulceration.
❑ Cholecystojejunostomy, choledochoduodenostomy, and choledochojejunostomy have partially replaced radical resection to bypass obstructing common bile duct extensions, thus decreasing the incidence of jaundice and pruritus.
❑ Whipple's operation, or pancreatoduodenectomy, has high mortality but can produce wide lymphatic clearance, except with tumors located near the portal vein, superior mesenteric vein and artery, and celiac axis. This rarely used procedure removes the head of the pancreas, the duodenum, and portions of the body and tail of the pancreas, stomach, jejunum, pancreatic duct, and distal portion of the bile duct.
❑Gastrojejunostomy is performed if radical resection isn't indicated and duodenal obstruction is expected to develop later.
Radiation therapy is usually ineffective except as an adjunct to chemotherapy or as a palliative measure.
Special considerations
Before surgery:
❑Ensure that the patient is medically stable, particularly regarding nutrition (this may take 4 to 5 days). If the patient can't tolerate oral feedings, provide total parenteral nutrition and I.V. fat emulsions to correct deficiencies and maintain positive nitrogen balance.
❑Give blood transfusions (to combat anemia), vitamin K (to overcome prothrombin deficiency), antibiotics (to prevent postoperative complications), and gastric lavage (to maintain gastric decompression), as ordered.
❑Tell the patient about expected postoperative procedures and expected adverse effects of radiation and chemotherapy.
After surgery:
❑ Watch for and report complications, such as fistula, pancreatitis, fluid and electrolyte imbalance, infection, hemorrhage, skin breakdown, nutritional deficiency, hepatic failure, renal insufficiency, and diabetes.
❑If the patient is receiving chemotherapy, treat adverse effects symptomatically.
Throughout this illness, provide meticulous supportive care:
❑Monitor fluid balance, abdominal girth, metabolic state, and weight daily. In weight loss, replace nutrients I.V., by mouth, or by NG tube; in weight gain (due to ascites), impose dietary restrictions, such as a low-sodium or fluid-retention diet, as ordered. Maintain a 2,500-calorie diet.
❑Serve small, frequent, nutritious meals by enlisting the dietitian's services. Administer an oral pancreatic enzyme at mealtimes if needed. Give an antacid to prevent stress ulcers as ordered.
❑To prevent constipation, administer laxatives, stool softeners, and cathartics, as ordered; modify diet; and increase fluid intake. To increase GI motility, position the patient properly at mealtime, and help him walk when he can.
❑Ensure adequate rest and sleep. Assist with range-of-motion (ROM) and isometric exercises, as appropriate.
❑Administer pain medication, antibiotics, and antipyretics, as ordered. Note time, site (if injected), and response.
❑Watch for signs of hypoglycemia or hyperglycemia; administer glucose or an antidiabetic agent, as ordered. Monitor blood glucose levels and response to treatment.
❑Document progression of jaundice.
❑Provide meticulous skin care to avoid pruritus and necrosis. Prevent excoriation in a pruritic patient by clipping his nails and having him wear cotton gloves.
❑Watch for signs of upper GI bleeding, test stools and vomitus for occult blood, and keep a flow sheet of Hb levels and HCT. To control active bleeding, promote gastric vasoconstriction with prescribed medication. Replace any fluid loss. Ease discomfort from pyloric obstruction with an NG tube.
❑To prevent thrombosis, apply antiembolism stockings and assist in ROM exercises. If thrombosis occurs, elevate the patient's legs, and give an anticoagulant or aspirin, as ordered.
❑When all treatments have failed, concentrate on keeping the patient comfortable and free from pain, and provide as much psychological support as possible. If the patient is going home, discuss continuing care needs with the caregiver or refer the patient to an appropriate home health care agency or hospice. Encourage the patient and caregiver to express their feelings and concerns. Answer their questions honestly, with tact and sensitivity.
Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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