Insulinoma Follow-up

Updated: Oct 03, 2017
  • Author: Zonera Ashraf Ali, MBBS; Chief Editor: Neetu Radhakrishnan, MD  more...
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Follow-up

Further Inpatient Care

After insulinoma resection, hyperglycemia may persist for 48-72 hours because of chronic down-regulation of insulin-receptors by the previously high circulating insulin levels secreted by the tumor and the suppression of normal pancreatic B cells. Small subcutaneous doses of insulin every 3-6 hours may be necessary if plasma glucose level exceeds 300 mg/dL (16.7 mmol/L).

Patients with major pancreatic resections may develop diabetes mellitus.

Streptozocin chemotherapy may be used for cytotoxic drug control of systemic disease. This chemotherapeutic agent appears to be toxic to cells producing insulin. For insulinomas, some cases of sustained improvement in hypoglycemic attacks have been reported, particularly when streptozotocin has been used.

Short-acting somatostatin analogues may be tried to control insulin release. In patients with unresectable metastatic disease to the liver, when systemic chemotherapy was unsuccessful, embolization of the hepatic artery and intraarterial chemotherapy may be indicated to control symptoms and hormone release, to inhibit tumor growth, and to improve survival. [54]

New therapy is currently under investigation.

  • OctreoTher consists of a somatostatin peptide analogue, labeled with a beta-emitter (yttrium-90). By targeting somatostatin-receptor–positive tumors (imaged by scan), it may deliver a local tumoricidal dose of radiation. [55]
  • OctreoTher binds to somatostatin receptor 2 and 3, has a mean path length of 5 mm, and a physical half-life of 64.1 hours.
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Inpatient & Outpatient Medications

Continue diazoxide and hydrochlorothiazide in patients who are not fit for surgery or when tumor resection was unsuccessful.

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Transfer

In advanced metastatic disease, the indications for chemotherapy or other interventional treatments must be emphasized in a multidisciplinary way and discussed with surgeons, specialists in chemoembolization, gastroenterologists, endocrinologists, and medical oncologists.

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Complications

See the list below:

  • Surgical complications (eg, pancreatic leakage) occur in about 14% of patients
  • Abscess
  • Other complications include intestinal obstruction, pleural effusion, hemorrhage, and fistula formation
  • Permanent diabetes mellitus may occur in about 5% of patients, mainly in those who undergo major pancreatic resections
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Prognosis

Approximately 90-95% of insulinomas are benign. Long-term cure with complete resolution of preoperative symptoms is expected after complete resection.

Recurrence of benign insulinomas was observed in 5.4% of patients in a series of 120 patients over a period of 4-17 years. The same diagnostic and therapeutic approach was recommended, including surgical exploration and tumor resection.

Indications for chemotherapy include progressive disease with an increase of greater than 25% of the main tumor masses in a follow-up period of 12 months, or tumor symptoms not treatable with other methods. Polychemotherapies have achieved better results than monochemotherapies.

The current medical treatment is based primarily on streptozotocin in combination with doxorubicin or 5-fluorouracil. Streptozotocin alone may achieve partial response in 50% of patients and complete response in 20%. The median survival in one study was 16 months.

If streptozotocin is combined with 5-fluorouracil, 33% of patients show complete response, with the median survival increasing to 26 months.

There is a single case report of successful control of intractable hypoglycemia in an elderly man with metastatic insulinoma through the use of oral rapamycin (sirolimus), 2 mg/d. [56]

Patients may develop nonfunctioning metastatic disease to the liver up to 14 years after insulinoma resection. [57] Note that some insulinomas are indolent (depending on the tumor biology), resulting in prolonged survival.

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