LETTERS TO THE EDITOR

 

Neuroendocrine tumors of the pancreas: keys issues in dealing with heterogeneity

Tumores neuroendocrinos de páncreas: claves para afrontar la heterogeneidad

 

 

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Key words: Pancreatic neuroendocrine tumors. Classification. Prognosis.

Palabras clave: Tumor neuroendocrino páncreas. Clasificación. Pronóstico.

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Dear Editor,

We thank Modesto Varas et al. (1) for their opportune comments with regard to the oncologic outcomes of our series of patients undergoing surgery for a pancreatic neuroendocrine tumor (PNET) (2). We agree with Varas et al. with respect to the increase in nonfunctional tumors (73%) and the figures of the incidental form of presentation (44%), which are in line with those from most series (3,4).

These authors contrast overall survival (OS) at five years from our series with their own series and that of Chheda. In our study, OS for stages I, II and III (European Neuroendocrine Tumor Society; ENETS) was 90.5%, 100% and 100%, respectively. These figures are similar to those reported by the largest series (3,4).

Given the heterogeneity of PNETs, we believe that it is crucial to stage tumors according to one of the established systems, either ENETS or the American Joint Cancer Commission/International Union Against Cancer (AJCC/UICC) (5), together with the degree of differentiation as defined by the World health Organization (WHO) (5).

We believe that generic terms such as "benign", "malignant", "local" and "locally advanced" should be avoided as they make the assessment of outcomes difficult.

In our series of 21 patients (26.5%) with liver metastases (stage IV), ten cases were resected (six with "curative" criteria, R0) and all were treated with cytostatics and therapies targeting the liver. In some nonrandomized studies, resection of the primary tumor in the presence of liver metastases has been associated with increased survival (5).

Once again, we thank Varas et al. for their interesting comments, which help to shed light on the diagnosis and treatment of PNETs.

 

Javier A. Cienfuegos, Fernando Rotellar and Miguel Ruiz-Canela
Department of General and Digestive Surgery.
Clínica Universidad de Navarra. Pamplona, Navarra. Spain

 

References

1. Varas M, Cugat E, Capdevilla J. Tumores neuroendocrinos pancreáticos. Rev Esp Enferm Dig 2017;109(6)480-1. DOI: 10.17235/reed.2017.4725/2016.         [ Links ]

2. Cienfuegos JA, Rotellar F, Salguero J, et al. A single institution's 21-year experience with surgically resected pancreatic neuroendocrine tumors: An analysis of survival and prognostic factors. Rev Esp Enferm Dig 2016;108:689-96.         [ Links ]

3. Ellison TA, Wolfgang CL, Chanjuan S, et al. A single institution's 26-year experience with nonfunctional pancreatic neuroendocrine tumors. A validation of current staging systems and a new prognostic nomogram. Ann Surg 2014,259:204-12. DOI: 10.1097/SLA.0b013e31828f3174.         [ Links ]

4. Birnbaum DJ, Turrini O, Ewald J, et al. Pancreatic neuroendocrine tumor: A multivariate analysis of factors influencing survival. Eur J Surg Oncol 2014;40:1564-71. DOI: 10.1016/j.ejso.2014.06.004.         [ Links ]

5. Bergsland EK, Woltering EA, Rindi G, et al. Neuroendocrine tumors of the pancreas. In: American Joint Committee on Cancer (AJCC), 8th edition, eds. AJCC Cancer Staging Manual. Chicago: Springer; 2017. p. 407-19.         [ Links ]