The gastrin receptor antagonist netazepide (YF476) in patients with type 1 gastric enterochromaffin-like cell neuroendocrine tumours: review of long-term treatment.

OBJECTIVE: Netazepide (YF476) is a recently developed, orally active gastrin receptor antagonist that, in short trials in patients with type 1 gastric enterochromaffin-like cell neuroendocrine tumours, has been shown to induce a significant reduction in the number and size of tumours as well as serum chromogranin A (CgA). The aim of this review is to evaluate the long-term effect and safety of netazepide. PATIENTS AND METHODS: Five patients previously treated with netazepide in an open-label trial were offered continuous treatment with netazepide 25 mg once daily. Upper endoscopy was performed every 6 months. The tumours were counted and measured, and tissue samples were obtained from the flat corpus mucosa. Enterochromaffin-like cell hyperplasia was classified according to Solcia and colleagues and volume density of CgA immunoreactive (IR) cells was calculated. Fasting serum CgA and fasting serum gastrin were measured every 3 months. RESULTS: All tumours regressed completely in three of five patients; time until total disappearance was 3, 9 and 12 months. In the other two patients, the number of tumours was reduced from 13 to 5 and from 14 to 3. Serum CgA showed a rapid and sustained decrease (P<0.001). The mean reduction in serum CgA was 4.1±0.5 nmol/l. Similarly, volume density of CgA IR cells in the flat corpus mucosa decreased (P<0.001), with the mean change being 2.0±0.4%. Serum gastrin and volume density of gastrin IR cells in the antral part of the stomach remained unchanged (P=0.2 and 0.7, respectively). CONCLUSION: Long-term administration of netazepide is effective and safe.

Follow-up of patients with ECL cell-derived tumours.

OBJECTIVES: To review the presentation, treatment and outcome of patients with type 1 gastric carcinoid tumours. MATERIAL AND METHODS: We retrospectively reviewed medical records and re-evaluated histopathological specimens of 26 patients with type 1 gastric carcinoids treated at a single tertiary referral centre from 1993 to 2013, with median time of follow-up 52.5 months (IQR 90.8). RESULTS: Seven patients (27%) had single tumours and 19 patients (73%) multiple tumours at the time of diagnosis. The median number of tumours and median diameter of largest tumour were 2.5 (IQR 3.2) and 6.0 mm (IQR 9.5) respectively. Median serum gastrin was 321.0 pmol/l (IQR 604.0) and median serum chromogranin A 7.7 nmol/l (IQR 5.3). Three patients had metastatic disease at the time of diagnosis and two developed metastases during follow-up. Patients with metastatic disease had larger primary tumours than the others (20.0 mm (IQR 28.5) vs. 5.0 mm (IQR 5.5), p = 0.04). There was a positive correlation between age and tumour size (r = 0.44, p = 0.03) and between serum chromogranin A and serum gastrin at diagnosis (r = 0.76, p = 0.001). Patients were either treated with surgery (n = 8 (31%)), a long-acting somatostatin analogue and/or gastrin receptor antagonist (n = 10 (39%)) for a period of time, or were observed without treatment (n = 8 (31%) with close endoscopic follow up. CONCLUSIONS: Although gastric carcinoids have an overall good prognosis, a significant proportion develops metastatic disease. As partial and total gastrectomy is associated with major side effects, treatment with long-acting a somatostatin analogue or gastrin antagonist should be considered.

The gastric mucosa 25 years after proximal gastric vagotomy.

OBJECTIVE: Vagotomy causes inhibition of basal and post-prandial acid secretion in humans, but the knowledge about the trophic effect of the vagal nerves is limited. Vagotomy is known to induce hypergastrinemia and we aimed to study the long-term effects of proximal gastric vagotomy (PGV) on the oxyntic mucosa and the enterochromaffin-like (ECL) cell density in particular. MATERIAL AND METHODS: Eleven patients operated with PGV because of duodenal ulcer and age- and sex-matched controls were examined 26 to 29 years postoperatively by gastroscopy with biopsies from the antrum and oxyntic mucosa. Neuroendocrine cell volume densities were calculated after immunohistochemical labeling of gastrin, the general neuroendocrine cell marker chromogranin A (CgA) and the ECL cell marker vesicular monoamine transporter 2 (VMAT2). Gastritis was graded and Helicobacter pylori (H. pylori) status was determined by polymerase chain reaction of gastric biopsies. Fasting serum gastrin and CgA were measured. RESULTS: Serum gastrin was higher in the PGV group compared to controls (median 21.0 [interquartile range (IQR) = 22.0] pmol/L vs 13.0 [IQR = 4.0] pmol/L, p = 0.04). However, there was neither a significant difference in serum CgA or in CgA (neuroendocrine) nor VMAT2 (ECL cell) immunoreactive cell volume density in the oxyntic mucosa. There was significantly more inflammation and atrophy in H. pylori-positive patients, but PGV did not influence the grade of gastritis. CONCLUSION: Despite higher serum gastrin concentrations, patients operated with PGV did not have higher ECL cell mass or serum CgA. Vagotomy may prevent the development of ECL cell hyperplasia caused by a moderate hypergastrinemia.

Gastric neuroendocrine carcinoma after long-term use of proton pump inhibitor.

We present a case of a gastric neuroendocrine carcinoma in a patient with a history of long-term proton pump inhibitor (PPI) use. A 49-year-old man using PPI for the last 15 years due to gastroesophageal reflux disease developed progressive dysphagia, dyspepsia and weight loss. Upper gastrointestinal endoscopy, endoscopic ultrasonography and abdominal CT diagnosed a malignant tumor localized to a hiatal hernia. Fasting serum chromogranin A and gastrin concentrations were elevated (32 nmol/l and 159 pmol/l, respectively). Helicobacter pylori PCR analysis of antral biopsies was negative. Biopsies from endoscopically normal oxyntic mucosa showed enterochromaffin-like (ECL) cell hyperplasia. Tumor biopsies revealed a poorly differentiated neuroendocrine carcinoma. Sevier-Munger staining, immunohistochemistry and electron microscopy indicated ECL cell as origin of the tumor cells. Concerns have previously been raised about the safety of long-term PPI use due to a possible increased risk of cancer. This case illustrates a patient with a poorly differentiated neuroendocrine carcinoma with ECL cell characteristics probably induced by hypergastrinemia secondary to long-term PPI use.

Five-year follow-up of patients treated for 1 year with octreotide long-acting release for enterochromaffin-like cell carcinoids.

BACKGROUND: Gastric carcinoids type 1 (GC1) are neuroendocrine tumors (NETs) arising from the enterochromaffin-like (ECL) cells in patients with chronic atrophic gastritis (CAG). The treatment of GC1 has been endoscopic polypectomy or surgical tumor excision and antrectomy. One year treatment with somatostatin analogs (SSAs) diminished tumor load and ECL cell density. The effect persisted 1 year after treatment was discontinued. However, the optimal SSA dose and treatment duration are unknown. OBJECTIVES: The aim of the present work was to study macroscopic and histopathological changes in the stomach and serum markers gastrin and chromogranin A (CgA) in GC1 patients 5 years after 1 year of octreotide long-acting release (LAR) treatment. MATERIAL AND METHODS: Five patients with GC1 were included 5 years after the initial year of octreotide LAR treatment. All patients underwent upper gastrointestinal endoscopy including tumor and mucosal biopsies from oxyntic mucosa, chest and abdominal computer tomography and octreotide scintigraphy. Fasting serum gastrin and CgA were also measured. RESULTS: At 5 years, one patient had a highly malignant gastric tumor, one patient had an increased number of GCs, regional and distant metastases and three patients had an increased number of GCs. Serum gastrin and CgA increased to pre-treatment levels after 1 year of follow-up and were unchanged at the 5-year follow-up. CONCLUSIONS: The disease had progressed in all five GCs patients treated with octreotide for 12 months at 5 years of follow-up. This suggests that, if started, octreotide treatment should not be discontinued in these patients.

A meal test improves the specificity of chromogranin A as a marker of neuroendocrine neoplasia.

Chromogranin A (CgA) is a neuroendocrine tumor (NET) marker. Modest CgA elevation is found in subjects with enterochromaffin-like (ECL) cell hyperplasia due to hypergastrinemia. Somatostatin analogs reduce CgA levels in patients with NET. Meals may affect serum CgA levels. The aims of the study were to investigate meal-induced CgA release and the short-term effect of octreotide on serum CgA levels. Four groups were studied: group A, seven patients with ECL cell hyperplasia secondary to use of proton pump inhibitors (PPIs); group B, six patients with gastric carcinoid type 1/ECL hyperplasia due to chronic atrophic gastritis (CAG); group C, six patients with nongastric NETs; group D, seven controls. The subjects were studied on three separate days with the use of three exposures: a test meal, pentagastrin subcutaneously (not group C), and octreotide intravenously. Serum CgA and gastrin were analyzed. A test meal induced a significant CgA increase in long-term PPI users and in healthy controls. The meal did not affect CgA levels in patients with gastric carcinoid type 1 or patients with NETs. The test meal increased gastrin levels in all groups except in those with CAG. Pentagastrin increased CgA levels in all groups tested except in those with CAG, while octreotide, reduced CgA and gastrin levels in all groups. Serum CgA should be determined in fasting individuals. A test meal may distinguish between increased CgA levels in PPI users from nongastric NET patients. Concomitant gastrin determination may help to discriminate between nongastric NETs and CAG. Intravenous octreotide rapidly reduces serum CgA.

Serum gastrin and chromogranin A levels in patients with fundic gland polyps caused by long-term proton-pump inhibition.

OBJECTIVE: Use of proton-pump inhibitors (PPIs) causes hypergastrinemia, and it is well known that gastrin has a trophic effect on the oxyntic mucosa. Some PPI users develop fundic gland polyps. The purpose of this study was to determine whether patients developing fundic gland polyps have a more pronounced gastric hypoacidity, hypergastrinemia or increased serum chromogranin A (CgA), which is an enterochromaffin-like (ECL) cell marker. MATERIAL AND METHODS: Five PPI users who developed multiple fundic gland polyps during PPI use were included in the study. PPI users without fundic gland polyps (n = 6) as well as healthy individuals (n = 6) were used as controls. In PPI users, we measured 24-h gastric pH, serum gastrin and CgA during one day, with standardized meals, whereas only gastrin and CgA were measured in the healthy individuals. Helicobacter pylori status was determined. RESULTS: Gastric pH, serum gastrin and CgA did not differ significantly between PPI users with and those without fundic gland polyps. All patients with fundic gland polyps were H. pylori negative, whereas 4 out of 6 PPI users without fundic gland polyps were H. pylori positive. Fasting CgA levels were elevated in all PPI users, and CgA more than doubled during the day in all groups. CONCLUSIONS: Fundic gland polyps induced by PPIs are not related to the level of hypergastrinemia. Serum CgA is markedly affected by meals and should be measured in samples from fasting patients.