Clinical symptoms, hormone profiles, treatment, and prognosis in patients with gastric carcinoids

The diagnosis and medical management of advanced neuroendocrine tumors

Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms that originate from endocrine glands such as the pituitary, the parathyroids, and the (neuroendocrine) adrenal, as well as endocrine islets within glandular tissue (thyroid or pancreatic) and cells dispersed between exocrine cells, such as endocrine cells of the digestive (gastroenteropancreatic) and respiratory tracts. Conventionally, NETs may present with a wide variety of functional or nonfunctional endocrine syndromes and may be familial and have other associated tumors. Assessment of specific or general tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Imaging modalities include endoscopic ultrasonography, computed tomography and magnetic resonance imaging, and particularly, scintigraphy with somatostatin analogs and metaiodobenzylguanidine. Successful treatment of disseminated NETs requires a multimodal approach; radical tumor surgery may be curative but is rarely possible. Well-differentiated and slow-growing gastroenteropancreatic tumors should be treated with somatostatin analogs or alpha-interferon, with chemotherapy being reserved for poorly differentiated and progressive tumors. Therapy with radionuclides may be used for tumors exhibiting uptake to a diagnostic scan, either after surgery to eradicate microscopic residual disease or later if conventional treatment or biotherapy fails. Maintenance of the quality of life should be a priority, particularly because patients with disseminated disease may experience prolonged survival.

Gastric neuroendocrine tumors

Gastric carcinoids are rare neuroendocrine tumors, usually classified as type I, if associated with atrophic body gastritis; type II, if associated with Zollinger-Ellison syndrome and multiple endocrine neoplasia type I, and type III, in the absence of any gastric pathology (sporadic tumors). The pathological features, as well as the prognosis of the tumor and the patient's survival strictly depend on this classification. The correct management of the patient with gastric carcinoid can only be proposed when the tumor has been classified by an accurate pathological and clinical evaluation of the patient. While the therapeutic approach in types I and II is based on a conservative strategy, including endoscopic resection, an adequate follow-up program, and the possible use of somatostatin analogues, an aggressive surgical approach is required in type III.

EUS may have limited impact on the endoscopic management of gastric carcinoids

Background. Carcinoids are occasionally found during gastroscopy. Endoscopic ultrasonography (EUS) can determine the depth of invasion and vascularity of submucosal tumors, including carcinoid tumors. Thus, EUS can lead to an informed decision as to whether to attempt endoscopic or surgical excision of a carcinoid. The three cases described here were found by EUS to be amenable to endoscopic resection of submucosal carcinoid tumors. In each case, the margin of the specimen obtained led to uncertainty regarding the completeness of gastroscopic excision of the tumor. Guidelines for follow-up of gastric carcinoid are few. The incompleteness of endoscopic resection of submucosal tumors, with tumor found at the specimen margin, indicates that careful follow-up and/or consideration of other means of excision are indicated.

Carcinoid tumors of the stomach

Interest in gastric carcinoid tumors has in recent time amplified considerably as the understanding of both their biological background and clinical significance has developed. The increase in identification associated with the widespread availability of upper gastrointestinal endoscopy has facilitated diagnosis. In addition concern related to the consequences of long-standing hypergastrinemia generated by the use of potent acid-suppressive medications has augmented both clinical and scientific focus on gastric neuro endocrine issues. The elucidation of the regulatory mechanisms of the progenitor cell (ECL cell) of the gastric carcinoid tumor, the refinement of a pathological grading system for ECL cell proliferation, and the availability of specific immunohistologic identification techniques have further amplified the characterization of this lesion. Although the putative malignant potential of gastric carcinoids may ultimately be of only modest concern in a background of hypergastrinemia its relationship to gastric adenocarcinoma is still enigmatic and worthy of further consideration. This review will describe the molecular interrelationship between low-acid states, gastrin, and ECL cell proliferation and will discuss the pathological classification of the distinct types of gastric carcinoid tumors. In addition, the clinical rationale of current diagnostic and therapeutic strategies will be examined, providing a logical basis for the formulation of appropriate management strategies for patient care.

Serum peptide profiles in patients with carcinoid tumors

BACKGROUND

Patterns of elevated serum peptides may reveal additional markers and permit better classification of tumors based on (secondary) peptide secretion.

METHODS

Fasting peptide profiles were obtained from 31 carcinoid patients. vasoactive intestinal peptide (VIP), pancreatic polypeptide (PP), neurotensin, substance P, gastrin-releasing polypeptide (GRP), calcitonin, gastrin, and pancreastatin were measured. Peptide elevation patterns were correlated with disease sites, syndrome, and survival.

RESULTS

Elevations in patients were as follows: VIP 0%, PP 13%, neurotensin 10%, substance P 20%, GRP 3%, calcitonin 10%, and gastrin 3%. There were no consistent patterns of elevated peptides with regard to site or syndrome. Pancreastatin was elevated in 81% of profiles and was the only abnormal peptide in 57% of patients.

CONCLUSION

Peptide profile results do not permit improved classification, predict syndrome development, or correlate with survival. In contrast, pancreastatin is elevated in most cases and may be utilized to monitor disease progression and evaluate response to therapy.

Prospective study of the ability of histamine, serotonin or serum chromogranin A levels to identify gastric carcinoids in patients with gastrinomas

BACKGROUND

Chronic hypergastrinaemia causes gastric enterochromaffin cell proliferation and carcinoid tumours. The only reliable means to diagnose enterochromaffin cell changes/carcinoids is by biopsy.

AIM

To assess whether serum histamine, chromogranin A or serotonin and urinary N-methylimidazoleacetic acid or 5-hydroxyindoleacetic acid correlate with advanced enterochromaffin cell changes or gastric carcinoids in patients with gastrinomas.

METHODS

Consecutive patients (n=145) had the above assays and endoscopy with gastric biopsies.

RESULTS

Lower N-methylimidazoleacetic acid and chromogranin A levels (P < 0.0001) occurred in disease-free patients. In patients with active disease, the fasting serum gastrin levels correlated (P < 0.0001) with both chromogranin A and N-methylimidazoleacetic acid levels. Chromogranin A (P=0.005), but not N-methylimidazoleacetic acid, serotonin, 5-hydroxyindoleacetic acid or histamine levels, correlated with the enterochromaffin cell index. Carcinoids, but not advanced enterochromaffin cell changes only, were associated with higher chromogranin A and N-methylimidazoleacetic acid levels.

CONCLUSIONS

Serum chromogranin A levels and urinary N-methylimidazoleacetic acid levels, but not serum histamine or serotonin or urinary 5-hydroxyindoleacetic acid, correlate with the presence of gastric carcinoids. However, no assay identified patients with advanced enterochromaffin cell changes only with high sensitivity/specificity. Thus, N-methylimidazoleacetic acid and chromogranin A levels are unable to identify patients with advanced changes in enterochromaffin cells and therefore neither can replace routine gastric biopsies.

Experience in treatment of metastatic pulmonary carcinoid tumors

BACKGROUND

The only cure for patients with pulmonary carcinoids is surgery. In the present paper, we report the results of medical treatment of patients with metastatic tumors, their circulating hormone markers, and immunohistochemical profile of the tumors.

PATIENTS AND METHODS/RESULTS

The response to systemic antitumoral treatment was studied in 31 patients with metastatic pulmonary carcinoids. Median survival from treatment start was 25 months. Alpha-interferon treatment has resulted in stable disease in 4 of 27 patients (median duration 15 months), while 23 patients showed progressive disease. Somatostatin analogues given as single drug treatment resulted in progressive disease. Streptozotocin and 5-fluorouracil resulted in progressive disease in seven of seven patients. Stable disease was obtained for 8 and 10 months respectively in two of two patients treated with streptozotocin + doxorubicin. Two of eight patients treated with cisplatinum + etoposide showed a significant decrease in tumor size lasting six and eight months respectively, and one displayed stable disease for seven months. Elevation of plasma chromogranin A was seen in 93%.

CONCLUSIONS

The results of systemic antitumoral treatment of pulmonary carcinoids with distant metastases are generally discouraging. Chemotherapy with cisplatinum + etoposide, or doxorubicin combined with streptozotocin or paclitaxel may be of value. Alpha-interferon and octreotide offer efficient symptomatic relief, but stabilizes tumor growth in merely 15% of the cases. Plasma chromogranin A is the most frequently elevated tumor marker.

Serum chromogranin A as a screening test for gastric enterochromaffin-like cell hyperplasia during acid-suppressive therapy

BACKGROUND

Serum chromogranin A (CgA), a marker of neuroendocrine neoplasia, increases during profound gastric acid inhibition, possibly reflecting the trophic effect of gastrin on the enterochromaffin-like (ECL) cells.

AIMS

This study investigated the clinical value of serum CgA as a screening test for gastric fundic enterochromaffin-like (ECL) cell hyperplasia during acid-suppressive therapy.

METHOD

A consecutive series of 230 dyspeptic patients referred for upper gastrointestinal endoscopy was investigated in a cross-sectional design. They were 154 patients on continuous medium-term (6 weeks to one year) or long-term (longer than one year) acid inhibition with either proton pump inhibitors (PPIs, n = 117) or histamine2-receptor antagonists (H2RAs, n = 37) for gastro-oesophageal reflux disease, and 76 nontreated subjects, with normal endoscopic findings (control group). Fasting blood samples were analysed for gastrin and CgA. Gastric biopsy specimens (oxyntic mucosa) were examined for histological evaluation of gastritis (Sydney classification) and of ECL cell hyperplasia (Solcia classification).

RESULTS

Serum CgA levels correlated positively with serum gastrin, following a quadratic function (r = 0.78, P < 0.0001). Elevated serum CgA values during long-term acid inhibition correlated with the presence and severity of fundic ECL cell hyperplasia. Multivariate analysis identified hypergastrinaemia (P < 0.0001), duration of acid inhibition (P < 0.0001), H. pylori infection (P = 0.008), ECL cell hyperplasia (P = 0.012), and body gland atrophy (P = 0.043) as independent predictors of elevated serum CgA. In subjects on long-term acid inhibition (n = 123), serum CgA was equally sensitive but more specific than serum gastrin for the detection of ECL cell hyperplasia (sensitivity, 91.3% for both; specificity, 73% vs. 43%, P < 0.0001).

CONCLUSIONS

During long-term gastric acid inhibition, serum CgA levels reflect the presence and severity of fundic ECL cell hyperplasia. Serum CgA is therefore a useful screening test for gastric ECL cell proliferative changes within this context.

ECL cell tumor and poorly differentiated endocrine carcinoma of the stomach: prognostic evaluation by pathological analysis

BACKGROUND & AIMS

Gastric endocrine tumors show a wide spectrum of clinical behavior, and prognostic assessement of individual tumors is difficult. The aims of this work were to identify predictors of tumor malignancy and patient outcome and to provide a rationale for treatment guidelines.

METHODS

Gastric endocrine tumors (86 enterochromaffin-like cell carcinoids and 16 poorly differentiated carcinomas) were investigated for 15 clinicopathologic variables and for expression of Ki67, P53, and BCL-2 proteins. Data were analyzed by univariate and multivariate statistics for evidence of tumor malignancy and patient survival.

RESULTS

Histological grades 2 and 3, size >/=3 cm, 9 or more mitoses, or >/=300 Ki67-positive cells per 10 high-power fields identified 26 of 33 (79%) malignant (metastatic or deeply invasive) tumors, and size <1 cm and/or growth restricted to the mucosa characterized 46 of 69 (67%) tumors with benign behavior during a median follow-up of 39 months. Malignancy-predictive models were developed using angioinvasion, size, clinicopathologic type, mitotic index, and Ki67 index. The same variables, in addition to deep gastric wall invasion and histological grade, predicted patient outcome.

CONCLUSIONS

Criteria for the assessment of malignancy risk and patient outcome were developed for the different tumors, providing a basis for treatment guidelines.