Prognostic value of margin clearance in total and distal pancreatectomy specimens with pancreatic ductal adenocarcinoma in a Danish population-based nationwide study

BACKGROUND: The prognostic role of resection margin status following total (TP) and distal (DP) pancreatectomy for pancreatic ductal adenocarcinoma (PDAC) is insufficiently evaluated. In Denmark, pancreatic surgery, including the postoperative pathological examination of the resection specimens, is confined to four centres, all reporting to the Danish Pancreatic Cancer Database (DPCD). In this Danish population-based nationwide study on TP and DP for PDAC from 2015-2019, based on data from DPCD, we evaluated whether there is a prognostically relevant minimum margin clearance definition and whether certain margins hold independent prognostic information.METHODS: Clinical and pathological data were retrieved from DPCD and supplemented by review of pathology reports and re-microscopy, if needed. One of the study pathologists performed all re-microscopy. The prognostic significance of margin status was evaluated by dichotomisation of the TP cohort (n = 101) and the DP cohort (n = 90) into involved and uninvolved groups, using different clearance definitions (0.5 - ≥3.0 mm).RESULTS: Following TP, direct involvement of the superior mesenteric artery (SMA) margin had independent prognostic value. When using a clearance definition of ≥ 0.5 or ≥ 1.5 mm for SMA, median survival for R0 versus R1 was 19 (95% CI 14-26) versus 10 (95% CI 5-20) months (p = 0.010), and 21 (95% CI 15-30) versus 10 (95% CI 8-19) months (p = 0.011), respectively. Overall margin status was not of significant prognostic importance following neither DP nor TP.CONCLUSION: In this Danish population-based nationwide study, SMA margin involvement was a significant isolated prognostic factor following TP, whereas combined assessment of all circumferential margins did not hold statistically significant prognostic information. Following DP, resection margin status did not affect survival.</p

Prognostic importance of margin clearance in ampullary adenocarcinoma following pancreaticoduodenectomy in a Danish population-based nationwide study

BACKGROUND: In this Danish nationwide population-based study, we evaluated the prognostically relevant minimum tumour-free margin width following pancreaticoduodenectomy (PD) for ampullary adenocarcinoma (AAC) and evaluated whether certain margins hold independent prognostic information.METHODS: We included 128 patients who underwent PD for AAC from 2015 to 2019. Clinical and pathological data including well-known prognostic factors were retrieved from the Danish Pancreatic Cancer Database. Missing data were obtained by review of pathology reports and re-microscopy of resection specimens. All PD specimens were examined using a standardised pathological protocol including multicolour inking, axial slicing and exact reporting of margin widths. The cohort was dichotomised into involved and uninvolved groups, using different margin clearance definitions (0.5-≥3.0 mm).RESULTS: Following PD for AAC, margin clearance of ≥1 mm was independently associated with improved chance of survival compared with &lt;1 mm (HR: 0.30, 95 % CI: 0.14-0.64 (p = 0.002)). Posterior and anterior margin widths were narrower compared with superior mesenteric artery and vein margins. Posterior margin and anterior surface had isolated prognostic significance in multivariable analysis.CONCLUSION: Following PD for AAC, margin clearance of at least 1 mm is independently associated with improved survival. Our data further indicate that anterior surface and posterior margin hold particular prognostic value.</p

Pre-existing TGF-β-specific T-cell immunity in patients with pancreatic cancer predicts survival after checkpoint inhibitors combined with radiotherapy

Background Circulating transforming growth factor-β (TGF-β)-specific T cells that recognize TGF-β-expressing immune regulatory cells have been described in patients with cancer. TGF-β-derived peptide vaccination modulates the tumor microenvironment and has shown clinical effects in animal models of pancreatic cancer (PC). TGF-β-expressing regulatory cells are especially elevated in PC and may prevent the clinical response to immune checkpoint inhibitors (ICIs). Thus, in the present study we investigated the significance of TGF-β-specific T-cell immunity in patients with PC treated with ICI combined with radiotherapy in a randomized phase 2 study (CheckPAC).Methods Immune responses to a TGF-β-derived epitope entitled TGF-β-15 as well as epitopes from Clostridium tetani (tetanus) and influenza were measured in peripheral blood mononuclear cells (PBMCs) with interferon-ɣ enzyme-linked immunospot assays. PBMCs were isolated before and after treatment. Correlations between immune response data and clinical data were evaluated with parametric and non-parametric statistical methods. Survival was analyzed with univariate and multivariate Cox-regression. TGF-β-15 specific T cells were isolated and expanded and examined for recognition of autologous regulatory immune cells by flow cytometry.Results PBMCs from 32 patients were analyzed for immune responses to the TGF-β-derived epitope entitled TGF-β-15. Patients with a strong TGF-β-specific immune response at treatment initiation had longer progression-free and overall survival, compared with patients with a weak or no TGF-β-specific immune response. This remained significant in multivariate analysis. Patients with weak and strong TGF-β-specific responses displayed similar responses towards viral antigens. Furthermore, we show that TGF-β-specific T cells from a clinical responder specifically reacted to and lysed autologous, regulatory immune cells. Finally, mimicking a TGF-β-15 vaccination, we showed that repeated stimulations with the TGF-β-15 epitope in vitro enhanced the immune response to TGF-β-15.Conclusion A strong TGF-β-15 specific immune response was associated with clinical benefit and improved survival after ICI/radiotherapy for patients with PC. Importantly, the lack of TGF-β-specific T cells in some patients was not caused by a general immune dysfunction. TGF-β-specific T cells recognized regulatory immune cells and could be introduced in vitro in patients without spontaneous responses. Taken together, our data suggest that combining TGF-β-based vaccination with ICI/radiotherapy will be beneficial for patients with PC