Treatment & Medication

Treatment

Medical Care

• Hypercalcemia: For patients with type 1 multiple endocrine neoplasia (MEN) who have hypercalcemia, surgery is the treatment of choice, including removal of 3.5 parathyroid glands.
• Gastrinoma: The current treatment consists of PPIs to reduce acid hypersecretion.
• Insulinoma: Surgery is the therapy of choice. Unresectable tumors are treated with diazoxide.
• Glucagonoma: Glucagonomas are surgically removed.
• VIPoma: Octreotide controls symptoms (diarrhea) in 80% of patients; however, surgical tumor removal should be attempted.
• Prolactinoma: Prolactinomas are treated with dopamine agonists, such as bromocriptine or cabergoline.
• GH-producing pituitary tumor: These tumors are treated by transsphenoidal surgery; in rare instances, medical therapy with a GH receptor antagonist is recommended.

Surgical Care

• Type 1 multiple endocrine neoplasia with hyperparathyroidism: In patients with type 1 multiple endocrine neoplasia (MEN) who have hyperparathyroidism, surgery is the treatment of choice if any of the following conditions are present:
  • Serum albumin–adjusted serum calcium level is more than 1 mg/dL of the upper limit of the reference range
  • Kidney stones
  • PTH-induced bone disease with a T score of -2.5
  • 24-hour urinary calcium excretion of more than 400 mg
• Type 1 multiple endocrine neoplasia with ZES
  • In patients with type 1 MEN with ZES, parathyroid surgery is indicated even in mild forms of hypercalcemia because serum calcium levels in the reference range are often associated with lower serum gastrin levels and consecutively lower gastric acid secretion (high calcium stimulates gastrin in those patients).
  • Removal of 3.5-4 parathyroid glands controls hypercalcemia. If 4 glands are removed, immediate autograft of parathyroid tissue into the musculature of the nondominant arm is indicated.
  • Some authors recommend taking careful operative notes and marking the residual parathyroid tissue with clips because reoperation in patients with type 1 MEN is likely.
• Gastrinoma
  • The role of surgery in ZES and type 1 MEN remains controversial because cure is only occasionally achieved. Most tumors are multicentric, raising the possibility of recurrence. Surgery may be indicated in patients with positive findings on imaging studies and no distant metastases.
  • Gastrinomas are found in the duodenal wall, in the pancreas, or in lymph nodes.
  • Local tumor excision is preferred, with larger tumors of the pancreatic body or tail removed by distal pancreatectomy. This approach may reduce the risk of subsequent metastatic disease to the liver.
  • Resection of liver metastases may be beneficial.
  • Total pancreatectomy is not indicated because of the deleterious effects of this procedure (eg, pancreatic exocrine insufficiency, diabetes mellitus).
• Insulinoma
  • Insulinomas are single large tumors that can be enucleated.
  • Resection may result in cure, although insulinomas in type 1 MEN may be multicentric.
  • Some authors recommend subtotal pancreatectomy (>80% of the pancreas) in patients with multiple tumors or when the tumor is not localized.
  • Surgical debulking in metastatic disease may reduce hypoglycemia to a certain extent.
  • Intraoperative ultrasonography facilitates tumor identification. Other methods include intraoperative monitoring of plasma glucose and insulin levels.
• VIPoma: In VIPoma, resection of single and multiple tumors is indicated, which may include a pancreatic tail resection.
• Carcinoid tumors: Carcinoid tumors are removed surgically; half of tumors are locally invasive or metastatic, particularly thymic carcinoids.
• Pituitary tumors
  • Transsphenoidal pituitary surgery is aimed at resection of any pituitary mass, particularly in acromegaly.
  • Patients with incomplete resection remain on treatment with dopamine agonists.
• Prolactinoma: Prolactinomas may be large and multicentric. The recurrence rate after surgical removal is high. Medical treatment is now the therapy of choice. Transsphenoidal surgery with external radiation therapy (external beam or gamma knife) is indicated in patients in whom long-term bromocriptine therapy is ineffective.
• Type 2 multiple endocrine neoplasia
  • Total thyroidectomy with radical lymph-node dissection is recommended in patients aged 5 years if a RET germline mutation is identified. All regional lymph nodes must be removed, even if they are not macroscopically suspected. Before any surgery, screening for pheochromocytomas must be performed. For those patients with germline mutations in codons 790/791, the age total thyroidectomy should be performed is controversial.
  • Pheochromocytomas require surgical excision under alpha-adrenergic blockade, starting 7-10 days before surgery (target blood pressure is 120/80 mm Hg while seated and systolic blood pressure is >90 mm Hg while standing/upright).

Medications

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Medical therapy is directed toward the specific endocrine syndromes.

Sandostatin acts similarly to the natural hormone somatostatin by suppressing peptide secretion from gastroenteropancreatic tumors.

Gastric acid secretion with PPIs is mandatory to prevent complications of gastric acid hypersecretion. PPIs are safe and cause no adverse effects even after long-term use. The goal is to reduce the basal acid output to levels less than 10 mEq/h 1 hour before the next dose in patients without previous acid-reducing gastric surgery and to kess than 5 mEq/h in patients with previous acid-reducing gastric surgery.

These agents inhibit insulin release from the tumor.

Reprinted with permission from eMedicine.com, 2008.
Available at: http://emedicine.medscape.com/article/923269-treatment.