No abstract

Background and objectives: The role of surgery in the treatment of nonfunctional pancreatic neuroendocrine carcinomas (PNEC) is not well defined. This study investigated the effect of surgical resection on cause-specific survival compared with nonoperative management.Methods: The Surveillance, Epidemiology, and End Results Program (SEER) database was utilized to identify patients with nonfunctional pancreatic neuroendocrine carcinoma diagnosed between January 1, 2004 and December 31, 2015. Survival was modeled using Kaplan-Meier analysis and multivariable Cox proportional hazards models.Results: Of the 488 patients identified, 137 (29%) underwent surgical resection of the primary site. Patients who underwent surgery had a median CSS of 31 months compared with 5 months in those who did not (p < 0.01). A survival benefit was observed when the cohort was stratified into local, nodal, and metastatic disease. Conclusion:Resection of the primary site in the cohort of PNEC patients compiled by SEER is associated with improved survival. Further consideration be placed on primary surgical resection for PNEC while additional studies that can select specifically for high-grade, poorly differentiated carcinomas need to be undertaken.

Background and ObjectivesThis study investigated the influence of the transcription factor SMAD4 on overall patient survival following surgical resection of pancreatic ductal adenocarcinoma (PDAC).MethodsThe SMAD4 status of 125 surgically resected PDAC specimens at a large academic center from 2014 to 2017 was routinely determined prospectively and correlated with clinicopathologic characteristics and overall survival.ResultsSMAD4 loss was identified in 62% of patients and was not associated with overall survival (OS). On multivariate Cox proportional hazards survival analysis, histologic grade was the best predictor of survival in the SMAD4(−) population (adjusted hazard ratio = 4.8, p < .0001). In the SMAD4(+) population, histologic grade was not associated with survival on multivariate analysis. In the SMAD4(−) population, median OS for well/moderately differentiated patients and poorly differentiated patients was 39.6 and 8.6 months, respectively.ConclusionIn this large cohort of resected PDAC, routine SMAD4 assessment identified a subpopulation of patients with SMAD4(−) and histologically poorly differentiated tumors that had significantly poor prognosis with median OS of 8.6 months. Characterization of the role of SMAD4 within the context of poorly differentiated tumors may help settle the controversy regarding SMAD4 in PDAC and lead to identification of personalized therapeutic strategies for subgroups of PDAC.

Purpose: STING (Stimulator of Interferon Genes) agonists are currently in development for treatment of solid tumors, including pancreatic ductal adenocarcinoma (PDAC). Response rates to STING agonists alone have been promising yet modest and combination therapies will likely be required to elicit their full potency. We sought to identify combination therapies and mechanisms that augment the tumor-cell intrinsic effect of therapeutically relevant STING agonists apart from their known effects on tumor immunity. Experimental Design: We screened 430 kinase inhibitors to identify synergistic effectors of tumor cell death with diABZI, an intravenously administered and systemically available STING agonist. We deciphered the mechanisms of synergy with STING agonism that cause tumor cell death in vitro and tumor regression in vivo. Results: We found that MEK inhibitors caused the greatest synergy with diABZI and that this effect was most pronounced in cells with high STING expression. MEK inhibition enhanced the ability of STING agonism to induce Type I interferon-dependent cell death in vitro and tumor regression in vivo. We parsed NF-κB-dependent and independent mechanisms that mediate STING-driven Type I interferon production and show that MEK signaling inhibits this effect by suppressing NF-κB activation. Conclusions: Our results highlight the cytotoxic effects of STING agonism on PDAC cells that are independent of tumor immunity, and that these therapeutic benefits of STING agonism can be synergistically enhanced by MEK inhibition.

<p>Supplementary Fig. 2 Tumor growth is inhibited by STING agonism and MEK inhibition in vivo.</p>