Pancreatic neuroendocrine tumors: glucagonoma
What is the treatment of a glucagonama?
Thoughtful preparation is crucial to control symptoms due to hormone-excess and to optimize the patient's condition for successful surgical removal of a glucagonoma. The skin rash resolves within a few days in about 90% of patients who are treated with a "somatostatin-analogue" medication (e.g., "octreotide"). A course of nutrition (either intravenously or with oral supplements or tube feedings) is also beneficial to those who have lost a substantial amount of weight, and this can also help relieve the rash. Blood sugar management is another critical consideration. Importantly, patients with glucagonomas are at risk (up to a 30% chance) of developing a deep vein thrombosis a blood clot that poses the hazard of embolizing (breaking off) to the lungs (pulmonary embolus) or to other organs. Therefore, preventative measures may be instituted, such as anticoagulation ("thinning the blood") with heparin-based medications or Coumadin, or the placement of a filter in the inferior vena cava to capture clots before they harm the lungs. Vaccinations may also be administered, in the event that a splenectomy is necessary along with the pancreas operation.
The primary treatment for a glucagonoma is surgical removal, and this offers the only chance for cure. An operation involves a full exploration of the abdomen, either through a standard open incision, or with laparoscopy, or with a combination of the two techniques. (see insulinoma). The surgeon determines the extent of the tumor and is hopefully able to remove all of it. This certainly includes the portion of the pancreas that contains the tumor, and it may also include sites of "metastases" (spread of the tumor elsewhere), such as local lymph nodes or segments of the liver. Because most glucagonomas are located in the pancreas tail or body, a "distal pancreatectomy" (removal of the left side of the pancreas) is appropriate for most patients, and this might involve the removal of the spleen as well. In that most glucagonomas are malignant, it is preferable to completely remove the tumor along with the surrounding normal pancreas tissue, rather than to simply "enucleate" (shuck out) the tumor itself. In anticipation of the patient requiring long-term octreotide injections, some surgeons will also remove the gallbladder because octreotide can promote the development of gallstones. A "pancreatoduodenectomy" ("Whipple resection") is necessary to remove a tumor in the head of the pancreas, but this is an uncommon location. It is often difficult to establish whether a glucagonoma is benign or malignant, based on microscopic features alone. As a result, some tumors are confirmed to be malignant only when tumor is discovered outside the pancreas, such as in local lymph nodes, the liver, or the lungs. About two-thirds of glucagonomas are malignant, and metastatic disease is common at the time of diagnosis. A cure is possible if all of the tumor can be surgically excised. Even when not all of a malignant glucagonoma can be removed, the elimination of the vast majority (>90%) of tumor can permit as many as 60%-80% of patients to survive five years, and this will also control symptoms in perhaps 85% of patients.