Thirty-day prevalence and clinical impact of fluid collections at the resection margin after distal pancreatectomy: Follow-up of a multicentric randomized controlled trial.

BACKGROUND: Postoperative fluid collections at the resection margin of the pancreatic stump are frequent after distal pancreatectomy, yet their clinical impact is unclear. The aim of this study was to assess the 30-day prevalence of postoperative fluid collections after distal pancreatectomy and the factors associated with a clinically relevant condition. METHODS: Patients enrolled in a randomized controlled trial of parenchymal transection with either reinforced, triple-row staple, or ultrasonic dissector underwent routine magnetic resonance 30 days postoperatively. Postoperative fluid collection was defined as a cyst-like lesion of at least 1 cm at the pancreatic resection margin. Postoperative fluid collections requiring any therapy were defined as clinically relevant. RESULTS: A total of 133 patients were analyzed; 69 were in the triple-row staple transection arm, and 64 were in the ultrasonic dissector transection arm. The overall 30-day prevalence of postoperative fluid collections was 68% (n = 90), without any significant difference between the two trial arms. Postoperative serum hyperamylasemia was more frequent in patients with postoperative fluid collections than those without (31% vs 7%, P = .001). Among the postoperative fluid collection population, an early postoperative pancreatic fistula (odds ratio 14.9, P = .002), post pancreatectomy acute pancreatitis (odds ratio 12.7, P = .036), and postoperative fluid collection size larger than 50 mm (odds ratio 6.6, P = .046) were independently associated with a clinically relevant postoperative fluid collection. CONCLUSION: Postoperative fluid collections at the resection margin are common after distal pancreatectomy and can be predicted by early assessment of postoperative serum hyperamylasemia. A preceding pancreatectomy acute pancreatitis and/or postoperative pancreatic fistula and large collections (>50 mm) were associated with a clinically relevant postoperative fluid collection, representing targets for closer follow-up or earlier therapeutic interventions.

Implications of pregnancy on MCN of the pancreas: A multicentric case-control study.

BACKGROUND: Mucinous cystic neoplasms (MCN) of the pancreas express estrogen and progesterone receptors. Several case reports describe MCN increasing in size during gestation. The aim of this study is to assess if pregnancy is a risk factor for malignant degeneration of MCN. METHODS: All female patients who underwent pancreatic resection of a MCN between 2011 and 2021 were included. MCN resected or diagnosed within 12 months of gestation were defined perigestational. MCN with high grade dysplasia or an invasive component were classified in the high grade (HG) group. The primary outcome was defined as the correlation between exposure to gestation and peri-gestational MCN to development of HG-MCN. RESULTS: The study includes 176 patients, 25 (14 %) forming the HG group, and 151 (86 %) forming the low grade (LG) group. LG and HG groups had a similar distribution of systemic contraceptives use (26 % vs. 16 %, p = 0.262), and perigestational MCN (7 % vs 16 %, p = 0.108). At univariate analysis cyst size ≥10 cm (OR 5.3, p < 0.001) was associated to HG degeneration. Peri gestational MCN positively correlated with cyst size (R = 0.18, p = 0.020). In the subgroup of 14 perigestational MCN patients 29 % had HG-MCN and 71 % experienced cyst growth during gestation with an average growth of 55.1 ± 18 mm. CONCLUSIONS: Perigestational MCN are associated to increased cyst diameter, and in the subset of patients affected by MCN during gestation a high rate of growth was observed. Patients with a MCN and pregnancy desire should undergo multidisciplinary counselling.

Resection to Exploration Ratios and Associated Outcomes in Patients with Pancreatic Ductal Adenocarcinoma.

OBJECTIVE: To investigate resection/exploration ratios (RER), reasons for omission of pancreatectomy, and survival outcomes in patients undergoing surgical exploration with resection intent for pancreatic ductal adenocarcinoma (PDAC). SUMMARY BACKGROUND DATA: While surgical indications for PDAC are expanding, information about intraoperative attrition is lacking. METHODS: The RER was calculated in PDAC patients undergoing exploration from 2018 through 2020. Factors associated with uncompleted resection and survival were identified using multivariable models. RESULTS: In total, 681 patients were included. Upfront explorations were 296 (43.7%), and post-neoadjuvant explorations were 385 (56.3%). The overall RER was 89.7% (90.5% in the upfront setting and 89.1% post-neoadjuvant treatment). In this latter subgroup, the RER decreased from 96.1% in resectable disease to 86.6% in borderline resectable disease and 61.9% in locally advanced disease. The primary reasons for uncompleted resection were occult metastases in presumed resectable/borderline resectable disease (without difference between upfront and post-neoadjuvant operations) and local unresectability in locally advanced disease. No preoperative variable was associated with uncompleted resection in upfront explorations, while anatomical staging informed the likelihood of surgical attrition following neoadjuvant treatment. Uncompleted resection was invariably associated with a median survival of around one year. The median post-pancreatectomy survival was 36.9 months in the upfront setting and 29.5 months following neoadjuvant treatment. The median survival from diagnosis in patients receiving post-neoadjuvant resection was 34.5 months. CONCLUSIONS: This analysis provided contemporary information about resection rates, reasons for intraoperative attrition, and survival outcomes in the entire spectrum of PDAC patients selected for surgical exploration at an experienced institution.

Molecular portraits of patients with intrahepatic cholangiocarcinoma who diverge as rapid progressors or long survivors on chemotherapy.

OBJECTIVE: Cytotoxic agents are the cornerstone of treatment for patients with advanced intrahepatic cholangiocarcinoma (iCCA), despite heterogeneous benefit. We hypothesised that the pretreatment molecular profiles of diagnostic biopsies can predict patient benefit from chemotherapy and define molecular bases of innate chemoresistance. DESIGN: We identified a cohort of advanced iCCA patients with comparable baseline characteristics who diverged as extreme outliers on chemotherapy (survival <6 m in rapid progressors, RP; survival >23 m in long survivors, LS). Diagnostic biopsies were characterised by digital pathology, then subjected to whole-transcriptome profiling of bulk and geospatially macrodissected tissue regions. Spatial transcriptomics of tumour-infiltrating myeloid cells was performed using targeted digital spatial profiling (GeoMx). Transcriptome signatures were evaluated in multiple cohorts of resected cancers. Signatures were also characterised using in vitro cell lines, in vivo mouse models and single cell RNA-sequencing data. RESULTS: Pretreatment transcriptome profiles differentiated patients who would become RPs or LSs on chemotherapy. Biologically, this signature originated from altered tumour-myeloid dynamics, implicating tumour-induced immune tolerogenicity with poor response to chemotherapy. The central role of the liver microenviroment was confrmed by the association of the RPLS transcriptome signature with clinical outcome in iCCA but not extrahepatic CCA, and in liver metastasis from colorectal cancer, but not in the matched primary bowel tumours. CONCLUSIONS: The RPLS signature could be a novel metric of chemotherapy outcome in iCCA. Further development and validation of this transcriptomic signature is warranted to develop precision chemotherapy strategies in these settings.

Contact system and intrinsic pathway activation in patients with advanced pancreatic cancer: a prospective cohort study.

BACKGROUND: Despite high risk of venous thromboembolism (VTE) in patients with pancreatic cancer, there are little data on contact system activation in these patients. OBJECTIVES: To quantify contact system and intrinsic pathway activation and subsequent VTE risk in patients with pancreatic cancer. METHODS: Patients with advanced pancreatic cancer were compared with controls. Blood was drawn at baseline and patients were followed for 6 months. Complexes of proteases with their natural inhibitors, C1-esterase inhibitor (C1-INH), antithrombin (AT), or alpha-1 antitrypsin (α1at), were measured for complexes containing kallikrein (PKa:C1-INH), factor (F)XIIa (FXIIa:C1-INH), and FXIa (FXIa:C1-INH, FXIa:AT, FXIa:α1at). The association of cancer with complex levels was assessed in a linear regression model, adjusted for age, sex, and body mass index. In a competing risk regression model, we assessed associations between complex levels and VTE. RESULTS: One hundred nine patients with pancreatic cancer and 22 controls were included. The mean age was 66 years (SD, 8.4) in the cancer cohort and 52 years (SD, 10.1) in controls. In the cancer cohort, 18 (16.7%) patients developed VTE during follow-up. In the multivariable regression model, pancreatic cancer was associated with increased complexes of PKa:C1-INH (P < .001), FXIa:C1-INH (P < .001), and FXIa:AT (P < .001). High FXIa:α1at (subdistribution hazard ratio, 1.48 per log increase; 95% CI, 1.02-2.16) and FXIa:AT (subdistribution hazard ratio, 2.78 highest vs lower quartiles; 95% CI, 1.10-7.00) were associated with VTE. CONCLUSION: Complexes of proteases with their natural inhibitors were elevated in patients with cancer. These data suggest that the contact system and intrinsic pathway activation are increased in patients with pancreatic cancer.

Clinical and Genomic Characterization of Pancreatic Ductal Adenocarcinoma with Signet-Ring/Poorly Cohesive Cells.

Signet-ring cell (SRC)/poorly cohesive cell carcinoma is an aggressive variant of pancreatic ductal adenocarcinoma (PDAC). This study aimed to clarify its clinicopathologic and molecular profiles based on a multi-institutional cohort of 20 cases. The molecular profiles were investigated using DNA and RNA sequencing. The clinicopathologic parameters and molecular alterations were analyzed based on survival indices and using a validation/comparative cohort of 480 conventional PDAC patients. The primary findings were as follows: (1) clinicopathologic features: SRC carcinomas are highly aggressive neoplasms with poor prognosis, and the lungs are elective metastatic sites; (2) survival analysis: a higher SRC component was indicative of poorer prognosis. In particular, the most clinically significant threshold of SRC was 80%, showing statistically significant differences in both disease-specific and disease-free survival; (3) genomic profiles: SRC carcinomas are similar to conventional PDAC with the most common alterations affecting the classic PDAC drivers KRAS (70% of cases), TP53 (55%), SMAD4 (25%), and CDKN2A (20%). EGFR alterations, RET::CCDC6 fusion gene, and microsatellite instability (3 different cases, 1 alteration per case) represent novel targets for precision oncology. The occurrence of SMAD4 mutations was associated with poorer prognosis; (4) pancreatic SRC carcinomas are genetically different from gastric SRC carcinomas: CDH1, the classic driver gene of gastric SRC carcinoma, is not altered in pancreatic SRC carcinoma; (5) transcriptome analysis: the cases clustered into 2 groups, one classical/exocrine-like, and the other squamous-like; and (6) SRC carcinoma-derived organoids can be successfully generated, and their cultures preserve the histologic and molecular features of parental SRC carcinoma. Although pancreatic SRC carcinoma shares similarities with conventional PDAC regarding the most important genetic drivers, it also exhibits important differences. A personalized approach for patients with this tumor type should consider the clinical relevance of histologic determination of the SRC component and the presence of potentially actionable molecular targets.

Endoscopic ultrasound fine-needle biopsy to assess DAXX/ATRX expression and alternative lengthening of telomeres status in non-functional pancreatic neuroendocrine tumors.

BACKGROUND/OBJECTIVES: Death domain-associated protein (DAXX) and/or α-thalassemia/mental retardation X-linked (ATRX) chromatin remodeling genes mutations and alternative lengthening of telomeres (ALT) activation are associated with more aggressive behavior of non-functional pancreatic neuroendocrine tumors (NF-PanNETs). We aimed to evaluate the reliability of such markers on endoscopic-ultrasound fine-needle biopsy (EUS-FNB) specimens. METHODS: Patients who underwent EUS-FNB and subsequent surgical resection for PanNETs between January 2017 and December 2019 were retrospectively identified. Immunohistochemistry (IHC) to evaluate DAXX/ATRX expression and fluorescence in situ hybridization (FISH) for ALT status were performed. Primary outcome was the concordance rate of markers expression between EUS-FNB and surgical specimens. Secondary aims were association between markers and lesion aggressiveness, their diagnostic performance in predicting aggressiveness, and agreement of preoperative and post-surgical Ki67-based grading. RESULTS: Forty-one NF-PanNETs (mean diameter 36.1 ± 26.5 mm) were included. Twenty-four showed features of lesion aggressiveness. Concordance of expressions of DAXX, ATRX, and ALT status between EUS-FNB and surgical specimens were 95.1% (κ = 0.828; p < 0.001), 92.7% (κ = 0.626; p < 0.001), and 100% (κ = 1; p < 0.001), respectively. DAXX/ATRX loss and ALT-positivity were significantly (p < 0.05) associated with metastatic lymphnodes and lymphovascular invasion. The combination of all tumor markers (DAXX/ATRX loss + ALT-positivity + grade 2) reached an accuracy of 73.2% (95%CI 57.1-85.8) in identifying aggressive lesions. Pre- and post-operative ki-67-based grading was concordant in 80.5% of cases (k = 0.573; p < 0.001). CONCLUSION: DAXX/ATRX expression and ALT status can be accurately evaluated in a preoperative setting on EUS-FNB samples, potentially improving the identification of patients with increased risk and poorer prognosis.

Characterization and digital spatial deconvolution of the immune microenvironment of intraductal oncocytic papillary neoplasms (IOPN) of the pancreas.

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a distinct entity from intraductal papillary mucinous neoplasms (IPMNs) and is considered one of the precursor lesions of pancreatic cancer. Through immunohistochemistry (IHC) and an artificial intelligence (AI)-based approach, this study aims at characterizing its immune microenvironment. Whole-slide IHC was performed on a cohort of 15 IOPNs, 2 of which harboring an associated adenocarcinoma. The following markers were tested: CD3, CD4, CD8, CD20, CD68, CD163, PD-1, PD-L1, MLH1, PMS2, MSH2, and MSH6. The main findings can be summarized as follows: (i) CD8+ T lymphocytes were the predominant immune cells (p < 0.01); (ii) the vast majority of macrophages were concurrently CD68+ and CD163+; (iii) all tumors showed an activated PD-1/PD-L1 axis, but none had mismatch repair deficiency; (iv) AI-based analysis revealed the presence of 2 distinct regions in each case, namely, Re1, localized at the center of the tumor, and Re2, located at tumor periphery; (v) the infiltrating component of the 2 invasive IOPNs showed a smaller extent of Re1 and a reduced rate of CD4+ cells, as well as a larger extent of Re2 and increased rate of CD8+ cells. IOPNs are lesions enriched in immune cells, with a predominance of CD8+ T lymphocytes and class 2 macrophages. Differently from IPMN-oncogenesis, the progression towards invasive carcinoma is accompanied by an increased rate of CD8+ lymphocytes. This finding may suggest the presence of an active self-immune surveillance in invasive IOPNs, potentially explaining, at least in part, the excellent survival rate of IOPN patients.

Long-term organoid culture of a small intestinal neuroendocrine tumor.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare and highly heterogeneous neoplasms whose incidence has markedly increased over the last decades. A grading system based on the tumor cells' proliferation index predicts high-risk for G3 NETs. However, low-to-intermediate grade (G1/G2) NETs have an unpredictable clinical course that varies from indolent to highly malignant. Cultures of human cancer cells enable to perform functional perturbation analyses that are instrumental to enhance our understanding of cancer biology. To date, no tractable and reliable long-term culture of G1/G2 NET has been reported to permit disease modeling and pharmacological screens. Here, we report of the first long-term culture of a G2 metastatic small intestinal NET that preserves the main genetic drivers of the tumor and retains expression patterns of the endocrine cell lineage. Replicating the tissue, this long-term culture showed a low proliferation index, and yet it could be propagated continuously without dramatic changes in the karyotype. The model was readily available for pharmacological screens using targeted agents and as expected, showed low tumorigenic capacity in vivo. Overall, this is the first long-term culture of NETs to faithfully recapitulate many aspects of the original neuroendocrine tumor.

The Impact of Molecular Subtyping on Pathological Staging of Pancreatic Cancer.

BACKGROUND: The long-term outcomes following surgical resection for pancreatic ductal adenocarcinoma (PDAC) remains poor, with only 20% of patients surviving 5 years after pancreatectomy. Patient selection for surgery remains suboptimal largely due to the absence of consideration of aggressive tumor biology. OBJECTIVE: The aim of this study was to evaluate traditional staging criteria for PDAC in the setting of molecular subtypes. METHODS: Clinicopathological data were obtained for 5 independent cohorts of consecutive unselected patients, totaling n = 1298, including n = 442 that underwent molecular subtyping. The main outcome measure was disease-specific survival following surgical resection for PDAC stratified according to the American Joint Commission for Cancer (TNM) staging criteria, margin status, and molecular subtype. RESULTS: TNM staging criteria and margin status confers prognostic value only in tumors with classical pancreatic subtype. Patients with tumors that are of squamous subtype, have a poor outcome irrespective of favorable traditional pathological staging [hazard ratio (HR) 1.54, 95% confidence interval (CI) 1.04-2.28, P = 0.032]. Margin status has no impact on survival in the squamous subtype (16.0 vs 12.1 months, P = 0.374). There were no differences in molecular subtype or gene expression of tumors with positive resection margin status. CONCLUSIONS: Aggressive tumor biology as measured by molecular subtype predicts poor outcome following pancreatectomy for PDAC and should be utilized to inform patient selection for surgery.

Acinar Cystic Transformation of the Pancreas: Histomorphology and Molecular Analysis to Unravel its Heterogeneous Nature.

Acinar cystic transformation (ACT) of the pancreas, previously called acinar cell cystadenoma, is a poorly understood and rare entity among pancreatic cystic lesions. This study aims to clarify its real nature. This research cohort included 25 patients with pancreatic ACT, representing the largest series in the literature. We describe their clinicopathological features and molecular profile using next-generation sequencing. ACT arose more often in women (F/M≃2:1), in the body-tail region, with a mean size of ~4 cm. At the latest follow-up, all patients were alive and disease free. Histologically, a typical acinar epithelium lined all cysts, intermingled with ductal-like epithelium in 11/25 (44%) cases. All the cases lacked any evidence of malignancy. Three ACT showed peculiar features: 1 showed an extensive and diffuse microcystic pattern, and the other 2 harbored foci of low-grade pancreatic intraepithelial neoplasia (PanIN) in the ductal-like epithelium. Next-generation sequencing revealed the presence of 2 pathogenic/likely pathogenic mutations in 2 different cases, 1 with ductal-like epithelium and 1 with PanIN, and affecting KRAS (c.34G>C, p.G12R) and SMO (c.1685G>A, p.R562Q) genes, respectively. The other case with PanIN was not available for sequencing. Overall, our findings support that ACT is a benign entity, potentially arising from heterogeneous conditions/background, including: (1) acinar microcysts, (2) malformations, (3) obstructive/inflammatory setting, (4) genetic predisposition, (5) possible neoplastic origin. Although all indications are that ACT is benign, the potential occurrence of driver mutations suggests discussing a potential role of long-term surveillance for these patients.

A dynamic analysis of empirical survival outcomes after pancreatectomy for pancreatic ductal adenocarcinoma.

BACKGROUND: Survival outcomes after pancreatectomy for pancreatic ductal adenocarcinoma may be biased by right-censoring. We herein analyzed a large dataset with no censored events for up to 5 years and dynamically investigated the impact of known prognostic factors, accounting for unobserved tumor characteristics. METHODS: Consecutive patients undergoing pancreatectomy from 2000 to July 2015 were included. The 1- to 5-year empirical survival rates were calculated, and factors associated with long-term survival (≥5 years) were analyzed using multivariable models. Dynamic analyses of survival and recurrence were conducted through landmarking, and the contribution of unobserved heterogeneity was estimated using frailty models. RESULTS: The study population included 1,048 patients. The median follow-up was 30.4 months in the whole cohort and 97.2 months in survivors. The median survival was 30.4 months, with empirical 1- to 5-year rates of 85.5%, 59.6%, 43.2%, 32.1%, and 27.5%. A favorable pathological profile was associated with 5-year survival, albeit 25.7% of long-survivors received an R1 resection, and 28.8% had N2 disease. The median recurrence-free survival was 17.2 months. At landmark analyses, baseline prognostic lost strength over time, with no independent predictors of survival being identified in the sets of patients alive at 4 and 5 years. There was a significant amount of unobserved heterogeneity in the early postoperative period. CONCLUSION: The 5-year post-pancreatectomy empirical survival was 27.5%. Dynamic analyses showed a time-varying structure of prognostic variables and a substantial impact of unobserved tumor characteristics that may drive the disease course under the selective pressure of surgical resection and adjuvant chemotherapy.

Integrative characterization of intraductal tubulopapillary neoplasm (ITPN) of the pancreas and associated invasive adenocarcinoma.

Pancreatic intraductal tubulopapillary neoplasm (ITPN) is a recently recognized intraductal neoplasm. This study aimed to clarify the clinicopathologic and molecular features of this entity, based on a multi-institutional cohort of 16 pancreatic ITPNs and associated adenocarcinomas. The genomic profiles were analyzed using histology-driven multi-regional sequencing to provide insight on tumor heterogeneity and evolution. Furthermore, an exploratory transcriptomic characterization was performed on eight invasive adenocarcinomas. The clinicopathologic parameters and molecular alterations were further analyzed based on survival indices. The main findings were as follows: 1) the concomitant adenocarcinomas, present in 75% of cases, were always molecularly associated with the intraductal components. These data definitively establish ITPN as origin of invasive pancreatic adenocarcinoma; 2) alterations restricted to infiltrative components included mutations in chromatin remodeling genes ARID2, ASXL1, and PBRM1, and ERBB2-P3H4 fusion; 3) pancreatic ITPN can arise in the context of genetic syndromes, such as BRCA-germline and Peutz-Jeghers syndrome; 4) mutational profile: mutations in the classical PDAC drivers are present, but less frequently, in pancreatic ITPN; 5) novel genomic alterations were observed, including amplification of the Cyclin and NOTCH family genes and ERBB2, fusions involving RET and ERBB2, and RB1 disruptive variation; 6) chromosomal alterations: the most common was 1q gain (75% of cases); 7) by transcriptome analysis, ITPN-associated adenocarcinomas clustered into three subtypes that correlate with the activation of signaling mechanism pathways and tumor microenvironment, displaying squamous features in their majority; and 8) TP53 mutational status is a marker for adverse prognosis. ITPNs are precursor lesions of pancreatic cancer with a high malignant transformation risk. A personalized approach for patients with ITPN should recognize that such neoplasms could arise in the context of genetic syndromes. BRCA alterations, ERBB2 and RET fusions, and ERBB2 amplification are novel targets in precision oncology. The TP53 mutation status can be used as a prognostic biomarker.

Loss of FGFR4 promotes the malignant phenotype of PDAC.

Transcriptomic analyses of pancreatic ductal adenocarcinoma (PDAC) have identified two major epithelial subtypes with distinct biology and clinical behaviours. Here, we aimed to clarify the role of FGFR1 and FGFR4 in the definition of aggressive PDAC phenotypes. We found that the expression of FGFR4 is exclusively detected in epithelial cells, significantly elevated in the classical PDAC subtype, and associates with better outcomes. In highly aggressive basal-like/squamous PDAC, reduced FGFR4 expression aligns with hypermethylation of the gene and lower levels of histone marks associated with active transcription in its regulatory regions. Conversely, FGFR1 has more promiscuous expression in both normal and malignant pancreatic tissues and is strongly associated with the EMT phenotype but not with the basal-like cell lineage. Regardless of the genetic background, the increased proliferation of FGFR4-depleted PDAC cells correlates with hyperactivation of the mTORC1 pathway both in vitro and in vivo. Downregulation of FGFR4 in classical cell lines invariably leads to the enrichment of basal-like/squamous gene programs and is associated with either partial or full switch of phenotype. In sum, we show that endogenous levels of FGFR4 limit the malignant phenotype of PDAC cells. Finally, we propose FGFR4 as a valuable marker for the stratification of PDAC patients.

"Pure" hepatoid tumors of the pancreas harboring CTNNB1 somatic mutations: a new entity among solid pseudopapillary neoplasms.

Hepatoid tumors (HTs) represent a rare group of neoplasms that are histologically similar to hepatocellular carcinoma but arise outside the liver. The current World Health Organization classification recognizes the hepatoid morphology of pancreatic tumors only as a possible variant of pancreatic ductal adenocarcinoma (PDAC). Here, we describe two cases of "pure" HT of the pancreas showing common features and characterized by indolent biological behavior. These tumors were roundish nodules with pushing borders, hyaline globules, and pure hepatoid histology; they were diffusely positive for ß-catenin and LEF1 on immunohistochemistry. At next-generation sequencing, both neoplasms harbored only one pathogenic somatic mutation that affected the CTNNB1 gene at exon 3 and showed a loss of heterozygosity on chromosomes 18 and 21. By integrating macroscopic and microscopic features, along with their molecular profiles, we advocate that such tumors represent a distinct entity from PDAC and should be considered a new variant of solid pseudopapillary neoplasms. The recognition of this new neoplastic category may have immediate implications not only for tumor taxonomy but also for clinical practice.

Ki-67 assessment of pancreatic neuroendocrine neoplasms: Systematic review and meta-analysis of manual vs. digital pathology scoring.

Ki-67 assessment is a key step in the diagnosis of neuroendocrine neoplasms (NENs) from all anatomic locations. Several challenges exist related to quantifying the Ki-67 proliferation index due to lack of method standardization and inter-reader variability. The application of digital pathology coupled with machine learning has been shown to be highly accurate and reproducible for the evaluation of Ki-67 in NENs. We systematically reviewed all published studies on the subject of Ki-67 assessment in pancreatic NENs (PanNENs) employing digital image analysis (DIA). The most common advantages of DIA were improvement in the standardization and reliability of Ki-67 evaluation, as well as its speed and practicality, compared to the current gold standard approach of manual counts from captured images, which is cumbersome and time consuming. The main limitations were attributed to higher costs, lack of widespread availability (as of yet), operator qualification and training issues (if it is not done by pathologists), and most importantly, the drawback of image algorithms counting contaminating non-neoplastic cells and other signals like hemosiderin. However, solutions are rapidly developing for all of these challenging issues. A comparative meta-analysis for DIA versus manual counting shows very high concordance (global coefficient of concordance: 0.94, 95% CI: 0.83-0.98) between these two modalities. These findings support the widespread adoption of validated DIA methods for Ki-67 assessment in PanNENs, provided that measures are in place to ensure counting of only tumor cells either by software modifications or education of non-pathologist operators, as well as selection of standard regions of interest for analysis. NENs, being cellular and monotonous neoplasms, are naturally more amenable to Ki-67 assessment. However, lessons of this review may be applicable to other neoplasms where proliferation activity has become an integral part of theranostic evaluation including breast, brain, and hematolymphoid neoplasms.

Circulating tumour DNA: a challenging innovation to develop "precision onco-surgery" in pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is predicted to become the third leading cause of cancer-related mortality within the next decade. Management of PDAC remains challenging with limited effective treatment options and a dismal long-term prognosis. Liquid biopsy and circulating biomarkers seem to be promising to improve the multidisciplinary approach in PDAC treatment. Circulating tumour DNA (ctDNA) is the most studied blood liquid biopsy analyte and can provide insight into the molecular profile and individual characteristics of the tumour in real-time and in advance of standard imaging modalities. This could pave the way for identifying new therapeutic targets and markers of tumour response to supplement diagnostic and provide enhanced stratified treatment. Although its specificity seems excellent, the current sensitivity of ctDNA remains a limitation for clinical use, especially in patients with a low tumour burden. Increasing evidence suggests that ctDNA is a pertinent candidate biomarker to assess minimal residual disease after surgery but also a strong independent prognostic biomarker. This review explores the current knowledge and recent developments in ctDNA as a screening, diagnostic, prognostic and predictive biomarker in the management of resectable PDAC but also technical and analytical challenges that must be overcome to move toward "precision onco-surgery."

401 consecutive minimally invasive distal pancreatectomies: lessons learned from 20 years of experience.

BACKGROUND: This study aimed to discuss and report the trend, outcomes, and learning curve effect after minimally invasive distal pancreatectomy (MIDP) at two high-volume centres. METHODS: Patients undergoing MIDP between January 1999 and December 2018 were retrospectively identified from prospectively maintained electronic databases. The entire cohort was divided into two groups constituting the "early" and "recent" phases. The learning curve effect was analyzed for laparoscopic (LDP) and robotic distal pancreatectomy (RDP). The follow-up was at least 2 years. RESULTS: The study population included 401 consecutive patients (LDP n = 300, RDP n = 101). Twelve surgeons performed MIDP during the study period. Although patients were more carefully selected in the early phase, in terms of median age (49 vs. 55 years, p = 0.026), ASA class higher than 2 (3% vs. 9%, p = 0.018), previous abdominal surgery (10% vs. 34%, p < 0.001), and pancreatic adenocarcinoma (PDAC) (7% vs. 15%, p = 0.017), the recent phase had similar perioperative outcomes. The increase of experience in LDP was inversely associated with the operative time (240 vs 210 min, p < 0.001), morbidity rate (56.5% vs. 40.1%, p = 0.005), intra-abdominal collection (28.3% vs. 17.3%, p = 0.023), and length of stay (8 vs. 7 days, p = 0.009). Median survival in the PDAC subgroup was 53 months. CONCLUSION: In the setting of high-volume centres, the surgical training of MIDP is associated with acceptable rates of morbidity. The learning curve can be largely achieved by several team members, improving outcomes over time. Whenever possible resection of PDAC guarantees adequate oncological results and survival.

Pancreatic surgery during COVID-19 pandemic: major activity disruption of a third-level referral center during 2020.

INTRODUCTION: The COVID-19 pandemic has severely limited the access to cancer surgery, but it is not known to what extent referral centers for pancreatic diseases were affected by its outbreak. The aim of this study is to describe the effect of COVID-19 pandemic on a third-level referral center for pancreatic surgery in Italy. METHODS: The 2020 activity of The Pancreas Institute of the University of Verona was reviewed, comparing different phases of the COVID-19 pandemic outbreaks using the pre-COVID era as a control. Endpoints were the overall caseload of pancreatic resections, surgical waiting list, administration of preoperative therapy, major morbidity and mortality, residents' training; number of inpatients beds, outpatient visits/procedures/diagnostics. RESULTS: In 2020, there was an overall significant reduction of pancreatic resections performed (394 vs. 506 in 2019), particularly during the first (March-May) and second (October-December) COVID-19 outbreaks, with an all-time-low of 16 resections/months in April (compared to 43 average resection/month in 2019). The rates of major morbidity (Clavien-Dindo ≥ 3) and mortality were similar to 2019 (16 vs 12%, p = 0.11 and 3 vs 2%, p = 0.29, respectively). During the first and second outbreaks resident's training, inpatient beds, outpatient visits, diagnostics, and procedures were severely impaired, while the waiting list for up-front cancer resections and the use of preoperative chemotherapy concomitantly raised. CONCLUSION: The COVID-19 pandemic has severely disrupted the activity of a third-level referral center for pancreatic surgery, affecting the access to cancer surgical procedures and raising concerns regarding the solidity of the current centralization model.

Non-functional pancreatic neuroendocrine tumours: ATRX/DAXX and alternative lengthening of telomeres (ALT) are prognostically independent from ARX/PDX1 expression and tumour size.

OBJECTIVE: Recent studies have found aristaless-related homeobox gene (ARX)/pancreatic and duodenal homeobox 1 (PDX1), alpha-thalassemia/mental retardation X-linked (ATRX)/death domain-associated protein (DAXX) and alternative lengthening of telomeres (ALT) to be promising prognostic biomarkers for non-functional pancreatic neuroendocrine tumours (NF-PanNETs). However, they have not been comprehensively evaluated, especially among small NF-PanNETs (≤2.0 cm). Moreover, their status in neuroendocrine tumours (NETs) from other sites remains unknown. DESIGN: An international cohort of 1322 NETs was evaluated by immunolabelling for ARX/PDX1 and ATRX/DAXX, and telomere-specific fluorescence in situ hybridisation for ALT. This cohort included 561 primary NF-PanNETs, 107 NF-PanNET metastases and 654 primary, non-pancreatic non-functional NETs and NET metastases. The results were correlated with numerous clinicopathological features including relapse-free survival (RFS). RESULTS: ATRX/DAXX loss and ALT were associated with several adverse prognostic findings and distant metastasis/recurrence (p<0.001). The 5-year RFS rates for patients with ATRX/DAXX-negative and ALT-positive NF-PanNETs were 40% and 42% as compared with 85% and 86% for wild-type NF-PanNETs (p<0.001 and p<0.001). Shorter 5-year RFS rates for ≤2.0 cm NF-PanNETs patients were also seen with ATRX/DAXX loss (65% vs 92%, p=0.003) and ALT (60% vs 93%, p<0.001). By multivariate analysis, ATRX/DAXX and ALT status were independent prognostic factors for RFS. Conversely, classifying NF-PanNETs by ARX/PDX1 expression did not independently correlate with RFS. Except for 4% of pulmonary carcinoids, ATRX/DAXX loss and ALT were only identified in primary (25% and 29%) and NF-PanNET metastases (62% and 71%). CONCLUSIONS: ATRX/DAXX and ALT should be considered in the prognostic evaluation of NF-PanNETs including ≤2.0 cm tumours, and are highly specific for pancreatic origin among NET metastases of unknown primary.