Zollinger-Ellison syndrome

Maintenance proton pump inhibition therapy and risk of oesophageal cancer

BACKGROUND

The association of long-term use of proton pump inhibitors (PPIs) with oesophageal adenocarcinoma has been poorly defined. Our aim was to assess the risk of oesophageal cancer assessing confounding by indication.

METHODS

This population-based cohort study included all 796,492 adults exposed to maintenance therapy with PPIs in Sweden in 2005-2012. Standardised incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated to assess the risk of oesophageal adenocarcinoma (and squamous cell carcinoma as a comparison) among long-term PPI users relative to the corresponding background population. The different indications for maintenance PPI therapy were analysed separately.

RESULTS

Among all individuals using maintenance PPI therapy, the overall SIR of oesophageal adenocarcinoma was 3.93 (95% CI 3.63-4.24). The SIRs of adenocarcinoma were increased also among individuals without gastro-oesophageal reflux disease who used PPIs for indications not associated with any increased risk of oesophageal adenocarcinoma. For example, the SIRs among participants using maintenance PPI therapy because of maintenance treatment with non-steroidal anti-inflammatory drugs and aspirin were 2.74 (95% CI 1.96-3.71) and 2.06 (95% CI 1.60-2.60), respectively. The SIRs of oesophageal squamous cell carcinoma were increased for most investigated indications, but to a lesser degree than for oesophageal adenocarcinoma.

CONCLUSION

In conclusion, the long term use of PPIs is associated with increased risk of oesophageal adenocarcinoma in the absence of other risk factors. Long term use of PPIs should be addressed with caution.

A two-center international evaluation of the Immulite 2000 automated serum gastrin assay

OBJECTIVES

To assess the performance of the Immulite 2000 serum gastrin assay.

DESIGN AND METHODS

Two-center validation and comparison with two manual gastrin assays.

RESULTS

Serum, serum separator, EDTA and heparin tube results differed <20%. Samples showed <20% degradation for <6 h at room temperature, 3-day-refrigerated, and underwent 3 freeze-thaw cycles. Imprecision was <8% between 20 and 824 ng/L (10-393 pmol/L). Spike recovery was 88.5-106%, and recovery on dilution was 62-135%. There were no interferences from gastrin 1-14, pentagastrin, and cholecystokinin (CCK) 1-33 and CCK 26-33. The fasting reference range was <100 ng/L (<48 pmol/L). Regression slopes to the manual assays were 0.9 and 0.97, with comparable clinical performance.

CONCLUSIONS

The Immulite 2000 assay is precise, accurate, and fast and compares well with established gastrin assays.

Zollinger-Ellison Syndrome

The first goal of therapy is the control of gastric acid hypersecretion using PPIs or high-dose H2R antagonists. The diagnosis of Multiple Endocrine Neoplasia (MEN I) should be established early in the disease. Localization of gastrinoma tumor should be performed using a combination of endoscopic ultrasonography (EUS), somatostatin receptor scintigraphy (SRS), and computerized tomography (CT), or Magnetic Resonance Imaging (MRI). Surgical resection in sporadic ZES should be performed to attempt cure of tumor. Surgery, hormonal, chemotherapy, embolization therapy or therapeutic OctreoScan should be considered in patients with metastatic tumor.

Gastrinomas demonstrate amplification of the HER-2/neu proto-oncogene

OBJECTIVE

This study determined whether genomic amplification of HER-2/neu or mutations of the p53 and ras genes were present in gastrinomas.

SUMMARY BACKGROUND DATA

Amplification of HER-2/neu, a proto-oncogene related to the epidermal growth factor receptor, and mutation of the ras proto-oncogene and p53 tumor suppressor gene appear to play a role in the pathogenesis of some human cancers. Little is known about possible molecular alterations in gastrinomas, tumors that may be particularly virulent because of gastrin overproduction, resulting in the severe ulcer diathesis, the Zollinger-Ellison syndrome.

METHODS

The differential polymerase chain reaction (PCR) procedure was used to detect amplification of the HER-2/neu gene in DNA samples from the novel human gastrinoma cell line (PT) and from paraffin-embedded samples of gastrinomas. Sequencing techniques were used to determine whether mutations of the p53 or ras (Ha-ras, N-ras, Ki-ras) genes were present.

RESULTS

Amplification (> twofold) occurred in all gastrinoma tumor samples. Compared with normal pancreas or ileum, a 4- to 12-fold amplification of HER-2/neu was found in 3 gastrinomas, 3 to 3.3-fold in four samples and 2.1- to 2.4-fold in the remaining five tumors. A heterozygous point mutation in the p53 gene (codon 273) was found in a single sample; none of the gastrinomas contained a mutation of the ras genes.

CONCLUSIONS

Amplification of the HER-2/neu gene, but not alterations of either p53 or ras, may be involved in the pathogenesis of gastrinomas. The unique PT cell line will be a useful model to further elucidate the molecular mechanisms that contribute to gastrinoma formation and growth.

Palliative treatment of neuroendocrine tumors

Effective palliation of patients with incurable neuroendocrine tumors requires both control of hormonal overproduction symptoms as well as control of tumor growth. Several important advances have been made in recent years toward these two goals. Octreotide and omeprazole have both been extremely effective in ameliorating hormonal symptoms of carcinoids, islet cell tumors and medullary thyroid carcinoma. Newer cytotoxic chemotherapy regimens and interferon have increased response rates over traditional therapy. More aggressive surgical extirpation of metastatic disease has also been beneficial.