Molecular strategies and 111in-labelled somatostatin analogues in defining the management of neuroendocrine tumour disease: a new paradigm for surgical management

Hepatic metastases from neuroendocrine tumors with a "thin slice" pathological examination: they are many more than you think

OBJECTIVES

To prospectively compare the results of the pathologic examination including thin 3- to 4-mm thick serial slices of the surgical specimen in a well-defined anatomic part of the liver with those of 4 different liver imaging techniques. BACKGROUNDS SUMMARY DATA: Liver metastases (LM) of neuroendocrine origin are frequent and accuracy of pretherapeutic liver imaging in detecting small-sized LM is questioned, but no study has compared the different techniques used to image large liver specimens and meticulous pathologic examination.

PATIENTS AND METHODS

Eleven patients with a metastatic endocrine tumor were selected before undergoing a right hepatectomy or a left hepatectomy passing along the median hepatic vein. Before the hepatectomy, patients underwent somatostatin receptor scintigraphy, computed tomography, magnetic resonance imaging, and ultrasonography (US). An intraoperative assessment (palpation and US) was also performed. Liver specimens were systematically cut into thin serial slices, 3- to 4-mm thick. A final histologic count of the total number of LM was obtained and compared with findings from each imaging technique.

RESULTS

Compared with the final histologic count of LM, fewer than 50% of the LM were detected preoperatively. The accuracy was 24% for somatostatin receptor scintigraphy, 38% for computed tomography and US, and 49% for magnetic resonance imaging (the only imaging technique that detected half the number of LM). The size of the smallest LM was not greater than 2 mm in 54% of the patients.

CONCLUSION

Half the number of LM from neuroendocrine tumors are undetectable on preoperative imaging.

Gastrointestinal carcinoids: the evolution of diagnostic strategies

Carcinoid tumors are rare, often insidious neoplasms arising from neuroendocrine cells. The majority arise in the gastrointestinal system, and are often incidentally found during investigation, although some may present as an emergency bleed or perforation. The prosaic symptoms of flushing, diarrhea, and sweating are often overlooked; thus, the diagnosis is usually much delayed and the tumor is advanced at presentation. This diagnostic delay renders effective management difficult and adversely affects outcome. This overview provides a current assessment of the evolution of the diagnostic techniques available to establish an accurate biochemical (5-hydroxyindole-3-acetic acid and chromogranin A) and topographic diagnosis (octreoscan, radio-labeled metaidobenzylguanidine, computerized tomography, magnetic resonance imaging, positron emission tomography, enteroclysis, endoscopic ultrasound, enteroscopy, capsule endoscopy, and angiography) of carcinoid tumors. The utility and shortcomings of the respective modalities available are evaluated. Although considerable advances have been made in establishing the diagnosis of carcinoid tumors and in defining the topography of metastatic disease, the major limitation is the inability to establish an early and timely diagnosis before the advent of metastatic disease.

A 50-year analysis of 562 gastric carcinoids: small tumor or larger problem?

OBJECTIVES

Interest in gastric carcinoid tumors has amplified considerably given the biological establishment of their relationship to gastrin and advances in the elucidation of the pathobiology of such lesions. The recognized propensity of acid-suppressing agents such as the proton pump inhibitor class of drugs to increase plasma gastrin levels has been proposed as a causal relationship in the apparent increase in the identification of such lesions although the increased prevalence of endoscopy and the enhanced awareness of pathologists have also been considered as contributory factors. We sought to examine if there has been an increase in gastric carcinoid incidence time correlative with these parameters.

METHODS

Carcinoid tumor cases from the End Results Group (1950-1969) and the Third National Cancer Survey (TNCS) (1969-1971) databases were combined with the most recent release of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registry (1973-1999); these three datasets revealed 13715 carcinoid cases, of which 562 were gastric in origin. Age-adjusted analyses as well as population-based gender and race correction ratios were completed in conjunction with United States decennial census data. To allow a finer granularity in incidence trends, the SEER database was divided into early (1973-1991) and late (1991-1999) subsets. RESULTS Since 1950, the percentage of gastric carcinoids among all gastric malignancies has increased from 0.3% to 1.77%. Since 1969, the proportion of gastric carcinoids among all enteric carcinoid lesions has increased from 2.4% to 8.7%. Age-adjusted incidence rates among male, female, black, and white population subsets have all increased since the TNCS time period, with the greatest increase (800%) noted in white females. The male:female ratio has fallen from 0.90 to 0.54. The occurrence of synchronous or metachronous noncarcinoid tumors with gastric carcinoid tumors has decreased by 26% during the course of SEER data collection. The 5-yr survival rate for gastric carcinoids overall has risen from 51% to 63% during the same time period.

CONCLUSIONS

Gastric carcinoids have increased in incidence over the last 50 yr. Differential increases in predominance across gender and race subdivisions may reflect genetic-based propensities (or protection) for gastric carcinoid tumors among certain ethnic populations. Increased endoscopic surveillance and associated sophisticated pathological evaluation of gastric biopsies undoubtedly are responsible for some of the observed increase in the incidence of gastric carcinoid tumors. These data allow no specific role to be assigned to the effects of acid-suppressive medications. Nevertheless the role of such agents cannot be discounted at this time since the time frame of the increased incidence is somewhat comparable to the introduction of these agents as is the known biological effect of gastrin on ECL cell proliferation.