zollinger-ellison%20syndrome
ZOLLINGER-ELLISON SYNDROME
Zollinger-Ellison syndrome (ZES) is a disease entity which refers to the triad of severe peptic ulcer disease (PUD), gastric acid hypersecretion and non-beta cell gastrin-secreting tumor primarily of the pancreas and duodenum (gastrinoma).
Approximately two-thirds of patients have sporadic ZES while the rest is part of multiple endocrine neoplasia type 1.
ZES should be considered in the differential diagnoses of patients who present with abdominal pain, malabsorption and chronic watery diarrhea.
A high index of clinical awareness is necessary to correctly diagnose ZES.

Surgical Intervention

  • Goal of surgery is primarily to prevent metastases
  • Surgical cure is likely high for extrapancreatic gastrinomas (eg gastrinomas in the duodenum or peripancreatic lymph nodes)
  • If preoperative imaging studies have shown clearly the location of the primary tumor & there are no metastases, extirpation should be attempted
  • If preoperative imaging studies are equivocal or negative, then intraoperative exploration to locate the tumor will be necessary
  • Patients with a sporadic gastrinoma w/o evidence of metastatic spread of disease should be offered exploratory laparotomy (regardless of imaging results) & resection w/ curative intent

Resection of Gastrinoma

Patients Who May Be Considered for Surgical Tumor Resection

  • Patients w/ sporadic ZES w/o liver or distant metastases or concomitant disease increasing surgical risk or limiting life expectancy
  • ZES patients who have MEN-1 & a gastrinoma >2 cm in size
    • Tumor size is a predictor of survival & development of liver metastases
    • Role of surgery is controversial since majority has multiple duodenal gastrinomas & often w/ lymph node metastases at the time of surgery
    • At present, surgery is still recommended only for lesions >2 cm on imaging & for persistent ZES after correction of hyperparathyroidism
    • Goal of surgery is to reduce risk of subsequent metastatic disease
    • For ZES patients who have MEN-1 w/ parathyroidism, it is recommended to have parathyroid surgery first
    • For MEN-1 patients whose ZES are controlled pharmacologically & who have not undergone surgery, monitoring of symptoms is important; imaging studies may be done as deemed important
  • Patients w/ recurrent ZES in whom tumors are identified & localized
Types of Surgical Procedures
  • Resection by enucleation is done for tumors that develop from the pancreatic head
    • Whipple procedure is not generally recommended & is only done for bigger tumors arising very near the pancreatic duct
  • Distal pancreatectomy is done for pancreatic tail lesions
  • Routine removal of pancreatic head lymph nodes & all regional lymph nodes are recommended
  • Curative resection is also possible for duodenal gastrinomas
  • Duodenotomy is recommended in all ZES patients undergoing surgery
    • Studies have shown that duodenotomy doubled the cure rate by 30-60% in ZES patients
    • Most effective method of identifying duodenal gastrinomas, w/c comprise 60% of all gastrinomas
  • Exploratory laparotomy may be done to locate a primary gastrinoma
    • If a primary tumor cannot be located, a search for ectopic tumors should be done
      • Defer a Whipple procedure in favor of closure then monitor every 6 mth w/ serial imaging to locate tumor
    • Common sites of ectopic gastrinomas: Pylorus, jejunum, liver, bile duct, ovary & omentum
    • Duodenectomy & intraoperative ultrasound may be done to help localize tumors

Parietal Cell Vagotomy

  • Appears to reduce the long-term need for acid-inhibitory pharmacologic treatment in patients who have recurrent or persistent disease, esp when complete resection of gastrinoma is not possible

Surgery for Patients w/ Metastatic Disease to the Liver

  • Hepatic resection is indicated for the treatment of metastatic liver disease in the absence of diffuse bilobar involvement, compromised liver function or extensive extrahepatic metastases
    • There is some evidence that resection of liver metastases improves survival
  • Cytoreductive surgery may be considered in patients w/ limited liver metastases
    • Current recommendation is to attempt liver resection if ≥90% appears resectable on preoperative imaging studies
  • Radiofrequency ablation (RFA) & cryoablation, done percutaneously or laparoscopically, are less morbid than hepatic resection & hepatic arterial embolization but may be applicable only to smaller lesions

Postoperative Assessment

  • Assessment of cure should be performed postoperatively in patients w/o metastases who underwent tumor resection
    • Fasting serum gastrin measurement or the secretin stimulation test should be done
  • History, PE, serum gastrin, CT & MRI imaging are recommended 3 & 6 mth postresection
    • Long-term surveillance includes history, PE, & tumor markers every 6-12 mth for the 1st 3 yr; subsequent follow-up & imaging studies are as clinically indicated
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