Autologous but not Fibrin Sealant Patches for Stump Coverage Reduce Clinically Relevant Pancreatic Fistula in Distal Pancreatectomy: A Systematic Review and Meta-analysis.

BACKGROUND: Postoperative pancreatic fistula (POPF) causes significant morbidity and mortality after distal pancreatectomy. Patch coverage of the pancreatic stump is often used with the intention to prevent POPF. Despite numerous investigations, the effects of patch coverage remain unclear. The present meta-analysis aims to clarify the effects of patch coverage in distal pancreatectomy on the incidence of POPF. METHODS: A systematic search of MEDLINE/PubMed and the Cochrane Database according to the PRISMA Statement was performed. Subsequently a meta-analysis on rates and overall incidence of POPF and length of hospital stay was carried out. By applying the inverse variance weighting method, the combined effect size and 95 % confidence interval were calculated. Heterogeneity was assessed using I 2 statistics. RESULTS: Five randomized controlled trials and six observational clinical studies were included for final analysis. A cumulative incidence of 43 % of POPF grades A-C was identified. Patch coverage in distal pancreatectomy is significantly associated with a decreased rate of POPF grade C (p = 0.006). Patches of autologous vascularized tissue significantly reduce the overall incidence of POPF (p = 0.04) and clinically relevant POPF grade B and C (p = 0.002). Fibrin sealant patches do not influence rates of POPF after distal pancreatectomy. None of the outcomes evaluated showed adverse results for the patch group. CONCLUSIONS: Patch coverage after distal pancreatectomy can reduce the rate of POPF. Patch coverage with autologous vascularized tissue but not fibrin sealant patches may be used to reduce clinically relevant POPF and postoperative morbidity in distal pancreatectomy.

Development of a reliable and accurate algorithm to quantify the tumor immune stroma (QTiS) across tumor types.

The tumor microenvironment plays an important role in the tumor biology. Overall survival of tumor patients after resection is influenced by tumor-infiltrating lymphocytes (TILs) as a component of the tumor stroma. However, it is not clear how to assess TILs in the tumor stroma due to heterogeneous methods in different cancer types. Therefore, we present a novel Quantification of the Tumor immune Stroma (QTiS) Algorithm to reliably and accurately quantify cells in the tumor stroma. Immunohistochemical staining of CD3 and CD8 cells in sections of metastatic colorectal cancer (mCRC), ovarian cancer (OvCa), hepatocellular carcinoma (HCC), and pancreatic ductal adenocarcinoma (PDAC), alltogether N = 80, was performed. Hot spots of infiltrating immune cells are reported in the literature. Reliability of the hot spot identification of TILs was examined by two blinded observers. Accuracy was tested in 1 and 3 hot spots using computed counting methods (ZEN 2 software counting (ZC), ImageJ software with subjective threshold (ISC) and ImageJ with color deconvolution (IAC)) and compared to manual counting. All tumor types investigated showed an accumulation of TILs in the tumor stroma (peri- and intratumoral). Reliability between observers indicated a high level consistency. Accuracy for CD8+/CD3+ ratio and absolute cell count required 1 and 3 hot spots, respectively. ISC was found to be the best for paraffin sections, whereas IAC was ideal for frozen sections. ImageJ software is cost-effective and yielded the best results. In conclusion, an algorithm for quantification of tumoral stroma could be established. With this QTiS Algorithm counting of tumor stromal cells is reliable, accurate, and cost-effective.