title: Conservative management and parenchyma-sparing resections of pancreatic neuroendocrine tumors: Literature review.
abstract: BACKGROUND
  Pancreatic neuroendocrine tumors (pNETs) are uncommon entities. pNETs are often small, slow growing, clinically silent neoplasms. However, they have an almost unpredictable biological behaviour with a not negligible malignant potential. Surgery still represents the treatment of choice, but the high morbidity associated to the enucleation or the formal pancreatectomy should be considered in the decision of the proper treatment. Management of these neoplasms is still debated, and indications for a conservative observational approach and for parenchyma sparing resections are not yet standardized.
  
  
  METHODS
  We review the state of art on the indications for the conservative management of pNETs. Searches on MEDLINE database were performed to identify articles reporting prognostic systems, biochemical screening, observational management, medical treatment and surgical strategies for pNETs.
  
  
  CONCLUSIONS
  Currently, an accurate 'wait-and-see' policy is recommended by the European Neuroendocrine Tumor Society (ENETS) only for non-functioning pNETs (NF-pNETs) <2 cm. A biochemical screening, based on sampling of serum levels of pancreatic polypeptide (PP) and chromogranin A, can address to early conservative surgery for MEN-1 associated NF-pNETs <2 cm to prevent their malignant transformation. The subtotal (80%) distal pancreatectomy first proposed by Thompson, often with the enucleation of possible pancreatic head tumors, still represents a good compromise between oncological radicality and prevention of pancreatic endocrine/exocrine insufficiency caused by standard radical resections for the treatment of inherited syndromes associated with NF-pNETs >2 cm and symptomatic F-pNETs of any size.
  
  
  CONCLUSIONS
  More studies are needed to further clarify and predict the biologic behaviour of pNETs and increase the indications for conservative observational management and parenchyma sparing pancreas resections.
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: claudio.mauriello@live.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Mauriello
authors.affiliation: Medical Officer, Italian Air Force Medical Corps, Ministry of Defence, Rome, Italy. Electronic address: dottornapolitano@gmail.com.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Napolitano
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: claudiog86@hotmail.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Gambardella
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: giancarlo.candela@unina2.it.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Candela
authors.affiliation: Department of Clinical and Experimental Medicine, Divisions of Oncology, School of Medicine, Second University of Naples, Italy. Electronic address: ferdinando.devita@unina2.it.
authors.forename: Ferdinando
authors.initials: F
authors.lastname: De Vita
authors.affiliation: Department of Clinical and Experimental Medicine, Divisions of Oncology, School of Medicine, Second University of Naples, Italy. Electronic address: michele.orditura@unina2.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Orditura
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: valerio.sciascia@gmail.com.
authors.forename: Valerio
authors.initials: V
authors.lastname: Sciascia
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: ernestart@msn.com.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Tartaglia
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: michelanz@fastwebnet.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Lanza
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: luigi.santini@unina2.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Santini
authors.affiliation: Department of Anaesthesiologic, Surgical and Emergency Sciences, Unit of General and Oncologic Surgery, School of Medicine, Second University of Naples, Italy. Electronic address: giovanni.conzo@unina2.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Conzo
mesh_terms: D006801:Humans; D018358:Neuroendocrine Tumors / Q000601:surgery; D010180:Pancreatectomy / Q000379:methods*; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D017410:Practice Guidelines as Topic
keywords: Conservative management; Intraoperative ultrasonography; Pancreatic neuroendocrine tumors; Parenchyma-sparing resections; Thompson procedure