Incomplete Picture

Neuroendocrine Neoplasms of the Gastrointestinal Tract by Prof. Dr. med. Matthias Schott, Prof. Dr. med. Günter Klöppel, PD Dr. med. Andreas Raffel, Prof. Dr. med. Andreas Saleh, Prof. Dr. med. Wolfram Trudo Knoefel und Prof. Dr. med. Werner A. Scherbaum in volume 18/2011

A review article can be expected to provide a critical appraisal of published scientific evidence, especially if the bibliography is updated to include 2011. This was not done to a sufficient degree in all subchapters on the diagnostic evaluation and treatment of gastroenteropancreatic neuroendocrine tumors (GEP-NET) (1).

The enormous importance of surgical resection undertaken with a curative intent, including surgery to lymph nodes and hepatic metastases in combination with microparticle liver embolization (transcatheter arterial embolization, TAE) and/or radiopeptide therapy in mostly metastasized NET was dealt with to an unsatisfactory extent. Such complex planning is currently the main task of an interdisciplinary NET center and preferably coordinated by an endocrinologist.

Current data on the basis of recent studies do not allow any conclusions about the mean progression time, mean progression-free survival, prolonging the median progression-free interval, and the median time to renewed progression (1). On this background, prolonging the progression-free interval by only six months by means of new molecular therapies (2) is highly unsatisfactory and would presumably hardly be what the authors intended.

The diagnosis of insulinoma in 2011 is based on the biochemical analysis of the unmistakable insulin secretion profile (3). This is recorded for 3–12 hours after glucose loading until neuroglucopenia. Without a secretion profile that is typical for an insulinoma, neuroglucopenia subsequently requires a selective intraarterial calcium injection test (SACI) (4). The 72 hour fasting test or C-peptide suppression test hardly helps to distinguish between patients with insulinoma and patients with pancreatic islet cell hyperplasia.

Pathologists often refer to the latter as nesidioblastosis, whereas clinicians prefer the term non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS). Measuring proinsulin is vital, in contrast to measuring C-peptides.

Testing for sulfonylureas is uncecessary; it implies that insulinoma patients are dissembling and also means that the indication was not clearly defined. In 30 years’ practice, we have never seen any reason to measure sulfonylureas, although we have diagnosed insulinoma in patients with a false-positive glibenclamide test result.

DOI: 10.3238/arztebl.2012.0066a

Prof. Dr. med. Achim A. R. Starke

Klinik für Endokrinologie und Diabetologie

Universitätsklinikum Düsseldorf

Prof. Dr. med. Peter E. Goretzki

Klinik für Viszeral- und Endokrine Chirurgie

Lukaskrankenhaus, Neuss

Dr. med. Christiane Saddig

Medizinische Klinik – Hämatologie/Onkologie,
Evangelisches Krankenhaus Düsseldorf

Conflict of interest statement

Dr Saddig has received expenses from Roche. The other authors declare that no conflict of interest exists.

References

1. Schott M, Klöppel G, Raffel A, Saleh A, Knoefel WT, Scherbaum WA: Neuroendocrine neoplasms of the gastrointestinal tract. Dtsch Arztebl Int 2011; 108(18): 305–12.

2. Raymond E, Dahan L, Raoul JL, et al.: Sunitinib malate for the treatment of pancreatic neuroendocrine tumors. N Engl J Med 2011; 364: 501–13.

3. Saddig C, Goretzki PE, Starke AAR: Differentiation of insulin secretion patterns in insulinoma. World J Surg 2008; 32: 918–29.

4. Placzkowski KA, Vella A, Thompson GB, Grant CS, Reading CC, Charboneau JW, Andrews JC, Service FJ: Secular trends in the presentation and management of functioning insulinoma at the Mayo Clinic, 1987–2007. J Clin Endocrinol Metab 2009; 94: 1069–73.