Prospective study of provocative angiograms to localize functional islet cell tumors of the pancreas

The role of interventional venous sampling in localising neuroendocrine tumours

PURPOSE OF REVIEW

This review focuses on the role of interventional venous sampling in the diagnosis and localization of neuroendocrine tumours (NETs), and its role in relation to conventional and novel imaging techniques.

RECENT FINDINGS

Imaging of NETs has evolved together with advances in imaging technology. Imaging localization plays an important role in the subsequent management of these tumours. This article provides an overview of the application of venous sampling in the localization of NETs, presented with current evidence to support its continued role in the diagnostic work-up of pituitary, parathyroid, pancreatic, adrenal and ovarian endocrine disease.

SUMMARY

Interventional venous sampling continues to be a highly sensitive modality in the localization of NETs. Although significant advances in noninvasive anatomic and functional imaging modalities have reduced the reliance of this well established technique, the latest literature continues to support its important role in the diagnostic armament of these unique and rare tumours.

The Current Role of Venous Sampling in the Localization of Endocrine Disease

Endocrine venous sampling plays a specific role in the diagnosis of endocrine disorders. In this article, we cover inferior petrosal sinus sampling, selective parathyroid venous sampling, hepatic venous sampling with arterial stimulation, adrenal venous sampling, and ovarian venous sampling. We review their indications and the scientific evidence justifying these indications in the diagnosis and management of Cushing's syndrome, hyperparathyroidism, pancreatic endocrine tumors, Conn's syndrome, primary hyperaldosteronism, pheochromocytomas, and androgen-secreting ovarian tumors. For each sampling technique, we compare its diagnostic accuracy with that of other imaging techniques and, where possible, look at how it impacts patient management. Finally, we incorporate venous sampling into diagnostic algorithms used at our institution.

Angiography and arterial stimulation venous sampling in the localization of pancreatic neuroendocrine tumours

Insulin- and gastrin-secreting neuroendocrine tumours of the pancreas are often very small at presentation because of the potent effects of their hormonal outputs, and they may therefore prove difficult to localize preoperatively. This is despite the advances made in recent years in cross-sectional imaging techniques, especially multidetector-row computed tomography and endoscopic ultrasound. In this chapter the techniques of angiography and arterial stimulation venous sampling used for the localization of these neoplasms are described; a combination of these two modalities provides both anatomical and functional data that are not available with other localization techniques, thereby improving operative outcome.

Localization of gastrinomas by selective intra-arterial calcium injection in patients on proton pump inhibitor or H2 receptor antagonist therapy

Preoperative localization is important for the successful treatment of gastrinomas. The aim of this study was to investigate whether selective intra-arterial calcium injection and hepatic venous sampling was able to localize gastrinomas in four patients who remained on proton pump inhibitor or H2 antagonist therapy. Calcium gluconate was injected directly into the arteries supplying the pancreas and liver after standard selective angiography. Gastrin levels were then measured in samples taken from the right hepatic vein. Calcium gluconate produced a diagnostic rise (at least 2-fold) in serum gastrin and unequivocally localized the tumour to a specific vascular territory in each case. One patient did not undergo surgery. In the remaining three patients, surgery confirmed the position and histology of the tumour. This study shows that in four patients with a confirmed gastrinoma we were able to localize the gastrinoma by selective intra-arterial calcium injection and hepatic venous sampling, whilst the patients remained on proton pump inhibitor or H2 antagonist therapy, thereby reducing their risk of gastrointestinal perforation.

Neuroendocrine Tumors of the Pancreas

Neuroendocrine tumors (NETs) are rare tumors of the endocrine pancreas that require a high degree of suspicion for timely diagnosis. Diagnosis is often delayed due to the nonspecific and intermittent presentation of symptoms. As many as 45% to 55% of tumors are nonfunctional and are typically diagnosed secondary to mass effect related symptoms or found incidentally. Functional tumors often are symptom specific and are diagnosed at an earlier stage than nonfunctional tumors. The challenging aspects of treating NETs are localizing the tumors, treating extensive or metastatic disease, and palliating symptoms. Most NETs have an indolent course, and aggressive multimodality treatment is often indicated and encouraged.

Multiple endocrine neoplasia type 1: duodenopancreatic tumors

Duodenopancreatic endocrine tumors are the most frequently lethal part of MEN-1. The management of these patients is complicated by the variable hormonal function of the tumors, and the often indolent but occasionally lethal nature of the tumors. This article reviews our current approach to the diagnosis, surveillance and management of these patients.

Multiple endocrine neoplasia type 1: duodenopancreatic tumours

The pancreaticoduodenal disease in Multiple endocrine neoplasia type 1 (MEN1) is the most frequent cause of death due to the syndrome, and the most controversial with regard to its management. This article discusses the current data and recommendations with respect to disease screening, functional tumour diagnosis, natural history, preoperative imaging, operative strategy and follow-up.

Imaging and localization of pancreatic insulinomas

For pancreatic insulinomas, the treatment of choice is surgical excision, which when successful is curative. Intraoperative palpation combined with ultrasonography theoretically depict almost all tumors, however the accuracy of palpation is improved by the preoperative localization. All recent advances in imaging have improved the likelihood for curative surgical resection. Our purpose is to demonstrate the characteristics of all modalities, which may be used in the preoperative localization algorithm.

Multiple endocrine neoplasias

Multiple endocrine neoplasia type 1 (MEN 1), and the multiple endocrine neoplasia type 2 syndromes (MEN 2A, MEN 2B, and familial non-MEN medullary thyroid carcinoma [FMTC]) encompass a wide range of endocrine problems, but arise from only two genes: the MEN 1 tumor suppressor gene and the RET proto-oncogene. MEN 1 is characterized by parathyroid hyperplasia, pancreaticoduodenal neuroendocrine tumors (PNTs), and pituitary adenomas. Surgery is the principal treatment modality for hyperparathyroidism and PNTs, but questions still remain concerning the timing and extent of surgery for PNTs. The MEN 2 syndromes are characterized by complete penetrance of medullary thyroid cancer. The MEN 2 syndromes differ in their variable expression of hyperparathyroidism, pheochromocytomas, and other clinical features. Genetic testing for mutations in the RET gene has revolutionized treatment by enabling thyroidectomies before significant disease occurs.

Duodenopancreatic resections in patients with multiple endocrine neoplasia type 1

OBJECTIVE

To review the authors' 7-year experience with a surgical approach for pancreatic and duodenal neuroendocrine tumors (NETs) in patients with multiple endocrine neoplasia type 1 (MEN 1) designed to remove all gross tumor with limited complications, preserving pancreatic function.

SUMMARY BACKGROUND DATA

MEN 1 is an autosomal dominant familial neoplasia syndrome characterized by the development of NETs of the duodenum and pancreas. Some tumors are clinically insignificant or follow a benign course, although a subset pursues a malignant, lethal natural history; the risk of surgical management must be appropriate to the disease course.

METHODS

The clinical, biochemical, genetic, and pathologic data were retrospectively reviewed for 21 consecutive MEN 1 patients undergoing pancreatic resection for NETs between 1993 and 1999 at one institution. Age at operation, presenting symptoms, results of preoperative and intraoperative localization studies, major and minor complications, and pathology, including metastases, were analyzed.

RESULTS

The surgical approach was selected based on the location and size of the tumors. Five patients required pancreaticoduodenectomy, 11 patients underwent non-Whipple pancreatic resections, and 5 underwent simple enucleation of benign NETs. The incidence of regional lymph node metastases was 33%.

CONCLUSIONS

Major pancreatic procedures can be performed safely in most patients with MEN 1 and NETs. Because NETs are the most common MEN 1-related cause of death in the authors' kindreds, an aggressive surgical approach, including early intervention before malignant spread and major pancreatic resection where indicated, appears justified.