Duodenopancreatic neuroendocrine tumors (DPNETs) aggressiveness is heterogeneous. Tumor grade and extension are commonly used for prognostic determination. Yet, grade classes are empirically defined, with regular up-dates changing the definition of classes. Genomic screening may provide more objective classes, and reflect tumor biology. The aim of this study was to provide a transcriptome classification of DPNETs. We included 66 DPNETs, covering the entire clinical spectrum of the disease in terms of secretion, grade, and stage. Three distinct molecular groups were identified, associated with distinct outcome (log-rank p<0.01): (i) better-outcome DPNETs with pancreatic beta-cell signature. This group was mainly composed of well-differentiated, grade 1 insulinomas; (ii) poor-outcome DPNETs with pancreatic alpha-cell and hepatic signature. This group included all neuroendocrine carcinomas and grade 3 DPNETs, but also some grade 1 and grade 2 DPNETs; and (iii) intermediate-outcome DPNETs with pancreatic exocrine and progenitor signature. This group included grade 1 and grade 2 DPNETs, with some insulinomas. Fibrinogen gene FGA expression was one of the top most expressed liver gene. FGA expression was associated with disease-free survival (HR=1.13, p=0.005), and could be validated on two independent cohorts. This original pathophysiologic insight provides new prognostic classification perspectives.
Marc Diedisheim, Solène Dermine, Anne Jouinot, Amandine Septier, Sébastien Gaujoux, Bertrand Dousset, Guillaume Cadiot, Etienne Larger, Jerome Bertherat, Raphael Scharfmann, Benoit Terris, Romain Coriat, and Guillaume Assié
Ophélie De Rycke, Thomas Walter, Marine Perrier, Olivia Hentic, Catherine Lombard-Bohas, Romain Coriat, Guillaume Cadiot, Anne Couvelard, Philippe Ruszniewski, Jérôme Cros, and Louis de Mestier
A rechallenge is common after the initial efficacy of alkylating-based chemotherapy (ALK) in pancreatic neuroendocrine tumors (PanNET). High MGMT expression seems associated with a lower response to ALK. We aimed to evaluate the efficacy and toxicity of ALK rechallenge in PanNET, and to assess the evolution of MGMT expression under ALK. All consecutive patients with advanced PanNETs who received initial ALK (achieving tumor control) followed by a pause of > 3 months, then an ALK rechallenge (ALK2) upon progression were retrospectively studied (cohort A). The primary endpoint was progression-free survival under ALK2 (PFS2). The MGMT expression was retrospectively assessed by immunohistochemistry (H-score) in consecutive PanNET surgically resected following ALK (cohort B). We found that Cohort A included 62 patients (median Ki67 8%), for whom ALK1 followed by a pause achieved an objective response rate of 55% and a PFS1 of 23.7 months (95% IC, 19.8–27.6). ALK2 achieved no objective response and stability in 62% of patients. The median PFS2 was 9.2 months (IC 95% 7.1–11.3). At multivariable analysis, a hormonal syndrome (P = 0.032) and a pause longer than 12 months (P = 0.041) were associated with a longer PFS2. In cohort B (17 patients), the median MGMT H-score increased from 45 (IQR 18–105) before ALK to 100 (IQR 56–180) after ALK (P = 0.003). We conclude that after the initial efficacy of ALK treatment, a pause followed by ALK rechallenge might be appropriate to prolong tumor control, improve quality of life and limit long-term adverse events. Increased MGMT expression under ALK might explain the low efficacy of ALK rechallenge.