Medical control of symptoms allows time for localization and nonemergent surgical treatment of the gastrinoma. A number of long-term studies have shown that the malignant potential of the tumor itself becomes the main determinant of survival (Figure 14-16).20 Thus, all patients with sporadic gastrinoma should be considered candidates for tumor localization and surgical exploration for cure. The management of patients with MEN type I and ZES is controversial and complex. In patients with MEN type I and primary hyperparathyroidism (HPT), the usual parathyroid pathology is multigland hyperplasia. It has been shown that successful neck exploration for resection of parathyroid hyperplasia can significantly reduce hypergastrine-mia (Figure 14-17) and improve symptoms. Therefore, patients with MEN type I, ZES, and HPT should undergo neck exploration prior to gastrinoma resection.21,22 Unfortunately, in this population, removal of pancreatic and duodenal tumors seldom cures patients of ZES,22 but resection of the primary gastrinomas does decrease the likelihood of liver metastases in these patients.23,24 In addition, the operative management of patients with MEN type I and gastrinoma is complicated by the fact that tumors tend to be multiple and small (4 to 6 mm) and usually involve the duodenum5 more often than other extrapancreatic sites. In these patients, the controversy centers on the fact that surgery is seldom curative, yet it may be effective to treat the
potential malignant disease and prevent eventual liver metastases. Although there is a wide range of opinion, we tend to operate on MEN type I patients when the primary tumor is 2 to 3 cm or larger.22,24 This is based on the fact that the presence of liver metastases correlates with primary tumor size. Four percent of patients with primary gastrinomas < 1 cm develop liver metastases, whereas 28% have liver metastases whose primary tumors are between 1 and 3 cm in diameter and 61% have tumors > 3 cm.23 After review of current data, it seems more prudent to operate on MEN type I patients with much smaller pancreatic and duodenal gastrinomas because this would tend to decrease the incidence of hepatic metastases.23,24
In patients with ZES and MEN type I, the evolution of intraoperative imaging methods has greatly facilitated exploration and resection. This is particularly true for small, multiple duodenal tumors that are difficult to locate. With improvement in intraoperative localization methods such as IOUS, IOE, and the secretin test,14 as well as increased awareness of duodenal tumors, some studies have reported that gastrinomas can be found and resected in an increasing number of patients with MEN type I and ZES. The experience of the surgeon appears to be another factor in achieving a good surgical outcome.2
In patients with ZES who have no clear localized disease, laparotomy is still indicated because recent series suggest that tumor will still be found,5 usually in the duodenum, and all regional lymph nodes should be removed for pathology review. Enucle-ation of pancreatic head tumors is usually sufficient, whereas distal or even subtotal pancreatectomy may be necessary for tumors of the body and tail. Studies have demonstrated similar outcomes whether enu-cleation or resection has been performed.25 In all patients with ZES, a careful examination of the duodenum is critical.
The conduct of the operation itself relies on a careful exploration of the abdomen and its contents and has been previously described.13 It is important to explore and palpate the liver, stomach, small bowel and mesentery, pancreas, and pelvis, including the uterus, fallopian tubes, and ovaries in female patients. An extended Kocher maneuver should be performed to mobilize the duodenum and gain access to the pancreatic head. The pancreatic body and tail may be better visualized by opening the gas-
trocolic ligament and mobilizing along the inferior border of the pancreas. Once this has been accomplished, the duodenum and pancreas can be fully palpated and examined by IOUS. IOUS may also be used to examine the liver. A 7.5 to 10 mHz near-field transducer is necessary for examining the pancreas, whereas the 2.5 to 5 mHz wide-angle transducer is best for the liver. Tumors appear sonolucent (see Figure 14-12) and should be imaged in three dimensions. The duodenum can then be palpated between thumb and forefinger for the presence of mass lesions. IOE with duodenal transillumination should also be performed. A duodenal gastrinoma appears as a photo-opaque mass lesion within the wall of the duodenum on transillumination (see Figure 14-14, A). The endoscopist may also visualize the tumor as a mucosal defect (see Figure 14-13). Once duodenal lesions are identified, they can be marked with suture and included within the confines of a modest longitudinal duodenotomy. Regardless of the results of IOUS or IOE, a duodenotomy is indicated in nearly all cases. This allows for visualization as well as a more careful palpation of the entire duodenal wall, particularly its medial portion. Suspicious nodules on the medial wall should not be excised until a catheter is passed through the ampulla of Vater to confirm its location. This may have to be accomplished by passing the catheter via the cystic duct into the common bile duct. Finally, the duodenum is preferably closed transversely in two layers to minimize the risk of leakage or obstruction (Figure
14-18, A and B). If a long duodenotomy is necessary, longitudinal closure is indicated (Figure 14-18, C). Regional lymph nodes should also be excised for pathologic examination. Reoperation for recurrent localized gastrinoma is also indicated if the tumor is imageable and results in elimination of all of the tumor in nearly every patient and complete remission in 30%.26 Further, following reoperation and removal of all identifiable gastrinoma, approximately one-third of patients are cured.26
Was this article helpful?