title: Is the 2-cm size cutoff relevant for small nonfunctioning pancreatic neuroendocrine tumors: A French multicenter study.
abstract: BACKGROUND
  Nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) are often discovered at a small size. No clear consensus exists on the management of NF-PNETs ≤ 2 cm. The aim of our study was to determine the prognostic value of indicators of malignancy in sporadic NF-PNETs ≤ 2 cm.
  
  
  METHODS
  Eighty patients were evaluated retrospectively in 7 French University Hospital Centers. Patients were managed by operative resection (operative group [OG]) or observational follow-up (non-OG [NOG]). Pathologic characteristics and outcomes were analyzed.
  
  
  RESULTS
  Sixty-six patients (58% women) were in the OG (mean age, 59 years; 95% CI, 56.0-62.3; mean tumor size, 1.6 cm; 95% CI, 1.5-1.7); 14 (72% women, n = 10) were in the NOG (mean age, 63 years; 95% CI, 56-70; mean tumor size, 1.4 cm; 95% CI, 1.0-1.7). All PNETs were ranked using the European Neuroendocrine Tumor Society grading system. Fifteen patients (19%) had malignant tumors defined by node or liver metastasis (synchronous or metachronous). The median disease-free survival was different between malignant and nonmalignant PNETs, respectively: 16 (range, 4-72) versus 30 months (range, 1-156; P = .03). On a receiver operating characteristic (ROC) curve, tumor size had a significant impact on malignancy (area under the curve [AUC], 0.75; P = .03), but not Ki-67 (AUC, 0.59; P = .31). A tumor size cutoff was found on the ROC curve at 1.7 cm (odd ratio, 10.8; 95% CI; 2.2-53.2; P = .003) with a sensitivity of 92% and a specificity of 75% to predict malignancy.
  
  
  CONCLUSIONS
  Based on our retrospective study, the cutoff of 2 cm of malignancy used for small NF-PNETs could be decreased to 1.7 cm to select patients more accurately.
authors.affiliation: Clinique de Chirurgie Digestive et Endocrinienne, Institut des Maladies de l'Appareil Digestif (IMAD), Hôtel Dieu, CHU de Nantes, Nantes, France. Electronic address: nicolas.regenet@chu-nantes.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Regenet
authors.affiliation: Service de Chirurgie Générale et Digestive, Hôpital Purpan, CHU de Toulouse, Toulouse, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Carrere
authors.affiliation: Clinique de Chirurgie Digestive et Endocrinienne, Institut des Maladies de l'Appareil Digestif (IMAD), Hôtel Dieu, CHU de Nantes, Nantes, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Boulanger
authors.affiliation: Service de Chirurgie Digestive et Endocrine, Hôpital Trousseau, CHU de Tours, Tours, France.
authors.forename: Loic
authors.initials: L
authors.lastname: de Calan
authors.affiliation: Service de Chirurgie Générale et Digestive, Hôpital Purpan, CHU de Toulouse, Toulouse, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Humeau
authors.affiliation: Service de Chirurgie Digestive et Endocrine, Hôpital Trousseau, CHU de Tours, Tours, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Arnault
authors.affiliation: Service de Chirurgie Viscérale et Endocrinienne Hôpital de la Miletrie, CHU de Poitiers, Poitiers, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Kraimps
authors.affiliation: Service de Chirurgie Digestive, Générale et Endocrinienne, Hôpital Dupuytren, CHU de Limoges, Limoges, France.
authors.forename: Murielle
authors.initials: M
authors.lastname: Mathonnet
authors.affiliation: Service de Chirurgie Digestive et Viscérale, Hôpital Hautepierre, CHU de Strasbourg, Strasbourg, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Pessaux
authors.affiliation: Service de Chirurgie Viscérale et Endocrinienne Hôpital de la Miletrie, CHU de Poitiers, Poitiers, France.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Donatini
authors.affiliation: Service de Chirurgie Digestive et Viscérale, Hôpital Hautepierre, CHU de Strasbourg, Strasbourg, France.
authors.forename: Aurelien
authors.initials: A
authors.lastname: Venara
authors.affiliation: Service de Chirurgie Viscérale, Hôpital Larrey, CHU d'Angers, Angers, France.
authors.forename: Niki
authors.initials: N
authors.lastname: Christou
authors.affiliation: Service de Chirurgie Digestive et Viscérale, Hôpital Hautepierre, CHU de Strasbourg, Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bachelier
authors.affiliation: Service de Chirurgie Viscérale, Hôpital Larrey, CHU d'Angers, Angers, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Hamy
authors.affiliation: Clinique de Chirurgie Digestive et Endocrinienne, Institut des Maladies de l'Appareil Digestif (IMAD), Hôtel Dieu, CHU de Nantes, Nantes, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Mirallié
mesh_terms: D000368:Aged; D015331:Cohort Studies; D018572:Disease-Free Survival; D019160:Endosonography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005602:France; D006801:Humans; D033162:Incidental Findings; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D010180:Pancreatectomy / Q000379:methods* / Q000401:mortality; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D049268:Positron-Emission Tomography / Q000379:methods; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D016896:Treatment Outcome; D047368:Tumor Burden