Pancreatic Resection

CHAPTER 14 Pancreatic Resection

Paul J. Foley, Jeffrey A. Drebin

Case Study

A 65-year-old male is referred to a surgeon for evaluation of a pancreatic mass. He reports a 2-month history of progressive jaundice, anorexia, and loss of 15 pounds. Additionally, he notes intermittent dull upper abdominal pain, light-colored stools, and tea-colored urine. He was recently seen by a gastroenterologist and underwent endoscopic retrograde cholangiopancreatography (ERCP), which showed narrowing of the distal common bile duct and pancreatic duct; a biliary stent was placed during the procedure. A subsequent computed tomography (CT) scan of the abdomen and pelvis showed a mass in the head of the pancreas without evidence of metastases or vascular encasement or invasion (Fig. 14-1).

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Figure 14-1 Computed tomography scan. There is a mass in the head of the pancreas (black arrowhead) adjacent to the duodenum (white arrowhead). A stent is seen in the intrapancreatic segment of the common bile duct (asterisk). The superior mesenteric artery (black arrow) and the superior mesenteric vein (white arrow) are not involved.

On physical examination, his sclerae are icteric. His abdomen is soft and nontender. No mass or lymphadenopathy is appreciated. Results of laboratory testing are remarkable for a conjugated hyperbilirubinemia and an elevated CA 19-9 level. Liver enzymes, amylase, and lipase levels are within normal limits.

BACKGROUND

The pancreas is a retroperitoneal structure located behind the stomach and lesser omentum; it is composed of four anatomic regions: head, neck, body, and tail. The head lies medial to the C-loop of the duodenum. The neck lies anterior to the mesenteric vessels and portal vein. The body and tail extend obliquely toward the hilum of the spleen. The uncinate process, an extension of the pancreatic head, wraps posteriorly around the superior mesenteric vessels.

The majority of pancreatic resections are performed for neoplasia. Generally, pancreaticoduodenectomy (Whipple procedure) is performed for lesions near the head of the pancreas and ampulla of Vater. Distal pancreatectomy is reserved for lesions of the body and tail. Total pancreatectomy, an infrequently performed procedure, is indicated for rare pancreatic malignancies that involve the entire gland. This chapter focuses on indications for and technical aspects of pancreaticoduodenectomy and distal pancreatectomy.

INDICATIONS FOR PANCREATIC RESECTION

Malignancies of the periampullary region are the most common indication for pancreaticoduodenectomy. These include primary pancreatic head and neck malignancies, distal common bile duct lesions, cancer of the ampulla of Vater, and periampullary duodenal cancers. Lesions localized to the body and tail of the pancreas (to the left of the mesenteric vessels) can be treated with distal pancreatectomy.

I. Pancreatic Adenocarcinoma: Surgical resection remains the only potentially curative therapy for adenocarcinoma of the pancreas. Pancreaticoduodenectomy is indicated for tumors of the pancreatic head, whereas body and tail lesions are treated with distal pancreatectomy and splenectomy. Because of the aggressive nature of most pancreatic tumors, most are diagnosed at an advanced stage and only 20% of lesions are resectable at the time of diagnosis. Locally advanced cancers are deemed unresectable if they extend beyond the pancreatic parenchyma and invade or encase adjacent vascular structures (e.g., the mesenteric vessels or portal vein). Patients with locally advanced tumors may be candidates for neoadjuvant therapy consisting of chemotherapy and radiation. Resection in this patient population is sometimes possible after treatment if tumor characteristics are favorable on repeat imaging studies. Patients with metastatic disease receive no survival benefit from pancreaticoduodenectomy, but may be offered palliative therapies. Nonsurgical palliative interventions include biliary stenting, chemotherapy, radiation, and chemical neurolysis of the celiac plexus. Surgical palliation, including Roux-en-Y hepaticojejunostomy or choledocojejunostomy to relieve biliary obstruction and gastrojejunostomy to relieve duodenal obstruction, are often performed simultaneously (i.e., double bypass) when metastatic disease is discovered at the time of surgical exploration. In patients with pancreatic cancer, the median survival time after resection with curative intent is 16 to 24 months. Patients with metastatic disease fare much worse, with a median survival of less than 6 months.

Pancreatic cancer is the fourth leading cause of cancer-related death in the United States.

II. Pancreatic Cystic Neoplasms: Cystic neoplasms of the pancreas include serous cystic neoplasms, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms (IPMNs). Combined, these represent fewer than 10% of all pancreatic neoplasms. Distinguishing cystic neoplasms from inflammatory pseudocysts, which are much more common, often poses a considerable diagnostic challenge. Smaller mucinous cystic neoplasms (<3 cm) with favorable imaging criteria and serous cystic neoplasms, which are almost always benign, may be monitored with serial imaging. In contrast, IPMNs are more likely to harbor invasive carcinoma and should generally be resected.
III. Pancreatic Neuroendocrine Tumors: Neuroendocrine tumors of the pancreas are a rare and heterogeneous group of lesions that includes insulinomas, glucagonomas, gastrinomas, somatostatinomas, and VIPomas. These tumors can arise sporadically or as a part of the multiple endocrine neoplasia (MEN) I syndrome. Symptoms result from overproduction of biologically active hormones. Gastrinomas are associated with the Zollinger-Ellison syndrome, which is characterized by gastric acid hypersecretion and intractable peptic ulcer disease. Gastrinomas and somatostatinomas are frequently malignant and should be resected with appropriate margins. Insulinomas are most often benign and can be enucleated. Insulinomas and glucagonomas are most often found in the body and tail of the pancreas. In contrast, somatostatinomas and gastrinomas are more often found in the pancreatic head.

MEN I is a hereditary syndrome characterized by parathyroid hyperplasia and tumors of the pancreatic islet cells and pituitary gland.

IV. Ampulla of Vater Neoplasms: Ampullary adenomas may be sporadic or associated with familial cancer syndromes, such as familial adenomatous polyposis (FAP). These adenomas are associated with a risk of malignant degeneration and are therefore treated with resection.
V. Periampullary Duodenal Neoplasms: Like ampullary adenomas, duodenal adenomas may be sporadic or may be associated with familial cancer syndromes, such as FAP or Peutz-Jeghers syndrome. Duodenal adenomas can progress to adenocarcinoma and should be removed when discovered. Inability to achieve complete excision, either endoscopically or via a transduodenal surgical approach, is an indication for pancreaticoduodenectomy. Duodenal adenocarcinoma is likewise treated with pancreaticoduodenectomy.
VI. Distal Common Bile Duct Strictures: Obstructive jaundice may result from benign or malignant biliary strictures. The most common cause of a benign stricture is iatrogenic injury (e.g., during cholecystectomy). Other causes include recurrent or chronic pancreatitis and choledocholithiasis. Malignant etiologies include primary bile duct cancers (cholangiocarcinoma) and pancreatic neoplasms. Pancreaticoduodenectomy is indicated if a malignant stricture is diagnosed or suspected.
VII. Sequelae of Chronic Pancreatitis: Inflammation of the pancreas can lead to scarring and stenosis of the pancreatic duct and common bile duct. Inflammatory masses in the setting of chronic pancreatitis and ductal strictures are often difficult to distinguish from pancreatic neoplasia. If the diagnosis of neoplasia cannot be excluded, such masses should be resected. Pancreatic resections may also be indicated for the management of intractable pain in the setting of chronic pancreatitis, although other operative procedures may be preferable.
VIII. Trauma: Injury to the pancreas may result from blunt or penetrating trauma. The management of pancreatic trauma is largely dependent on the severity and location of injury. Penetrating injuries to the head of the pancreas are typically associated with concomitant injuries to surrounding structures, including the duodenum, bile duct, or liver. Severe devitalizing injuries to the pancreatic head, duodenum, and distal common bile duct may require pancreaticoduodenectomy. The mortality rate associated with a Whipple procedure performed in this setting approaches 60%. Injuries localized to the body and tail are best treated with a distal resection, with or without splenectomy.

PREOPERATIVE EVALUATION

I. History and Physical Examination: In the patient with a pancreatic mass, a history of abdominal pain, back pain, loss of appetite, vomiting, weight loss, and jaundice, should be elicited. Back pain may indicate invasion of a tumor into the retroperitoneum. Vomiting suggests a gastric outlet obstruction. In the presence of metastatic disease, physical examination may reveal an umbilical nodule (Sister Mary Joseph’s node) or left supraclavicular lymphadenopathy (Virchow’s node). Digital rectal examination may reveal peritoneal implants in the pelvis (Blumer’s shelf).

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May 26, 2018 | Posted by in GENERAL SURGERY | Comments Off on Pancreatic Resection

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