Morphologic Characterization of Pancreatic Ductal Adenocarcinoma following Post-neoadjuvant Pancreatectomy and Clinical value of Intratumor Heterogeneity.

OBJECTIVE: To evaluate the morphologic landscape of pancreatic ductal adenocarcinoma (PDAC), intratumor spatial heterogeneity, and the resulting clinical impact following post-neoadjuvant pancreatectomy. SUMMARY BACKGROUND DATA: The clinical value of PDAC morphologic subtypes and intratumor spatial heterogeneity post-treatment remains an open issue. MATERIALS AND METHODS: The study cohort included patients who underwent post-neoadjuvant pancreatectomy for PDAC at the University of Verona Hospital Trust between 2013 and 2019. All hematoxylin and eosin-stained slides were reviewed to assess PDAC histomorphology and intratumor heterogeneity. The relationship with other clinicopathological variables, overall survival (OS), and recurrence-free (RFS) survival was evaluated using standard statistics. RESULTS: The study cohort included 400 patients. Histological revision identified ten different morphologic subtypes. Gland-forming PDAC with a conventional pattern was the most frequently identified subtype (41.8%). Overall, 247 tumors (61.7%) showed only one histological pattern and were classified as homogeneous, whereas 153 (38.3%) showed different morphologies and were classified as heterogeneous tumors. The median post-resection survival was 30.1 months (95%CI 26.6-33.5). There was a substantial survival variability according to the morphologic subtype, ranging from 19.1 months in the gyriform subtype to 47.0 months in the papillary subtype. Tumors with a heterogeneous morphology displayed a higher rate of nodal metastases, worse tumor regression metrics, and worse oncologic outcomes relative to spatially homogeneous tumors. DISCUSSION: This paper provided a morphological taxonomy of residual tumors following post-neoadjuvant pancreatectomy for PDAC. The morphologic subtype and intratumor spatial heterogeneity have relevant prognostic implications and could be included in the pathology report to complement regression metrics.

Reappraising the Role of Intraoperative Neck Margin Revision in Post-Neoadjuvant Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma: A Multi-Institutional Analysis.

OBJECTIVE: To investigate whether revision of pancreatic neck margin based on intraoperative frozen section analysis has oncologic value in post-neoadjuvant pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC). SUMMARY BACKGROUND DATA: The role of intraoperative neck margin revision has been controversial, with little information specific to post-neoadjuvant PD. METHODS: Patients who underwent post-neoadjuvant PD (2013-2019) for conventional PDAC with frozen section analysis of neck margin at three academic institutions were included. Overall survival (OS) and recurrence-free survival (RFS) were compared across three groups: complete resection achieved en-bloc (CR-EB), complete resection achieved non-en-bloc (CR-NEB), and incomplete resection (IR). RESULTS: Among the 671 patients included, 524 (78.1%) underwent CR-EB, 119 (17.7%) CR-NEB and 28 (4.2%) IR. Patients undergoing CR-NEB and IR exhibited larger tumors and lower rates of RECIST response, requiring vascular resections more often. Likewise, CR-NEB and IR were associated with a worse pathological profile than CR-EB. The incidence of postoperative complications and access to adjuvant treatment were comparable among groups. A CR-EB was associated with the longest OS duration (34.3 mo). In patients with positive neck margin, obtaining a CR-NEB via re-excision was associated with a comparable OS relative to patients with an IR (26.9 vs. 27.1 mo, P=0.901). Similar results were observed for RFS. At multivariable analysis, neck margin status was not independently associated with survival and recurrence. CONCLUSION: Conversion of an initially positive pancreatic neck margin by additional resection is not associated with oncologic benefits in post-neoadjuvant PD and cannot be routinely recommended.

DNA Methylation Profiling Enables Accurate Classification of Nonductal Primary Pancreatic Neoplasms.

BACKGROUND & AIMS: Cytologic and histopathologic diagnosis of non-ductal pancreatic neoplasms can be challenging in daily clinical practice, whereas it is crucial for therapy and prognosis. The cancer methylome is successfully used as a diagnostic tool in other cancer entities. Here, we investigate if methylation profiling can improve the diagnostic work-up of pancreatic neoplasms. METHODS: DNA methylation data were obtained for 301 primary tumors spanning 6 primary pancreatic neoplasms and 20 normal pancreas controls. Neural Network, Random Forest, and extreme gradient boosting machine learning models were trained to distinguish between tumor types. Methylation data of 29 nonpancreatic neoplasms (n = 3708) were used to develop an algorithm capable of detecting neoplasms of non-pancreatic origin. RESULTS: After benchmarking 3 state-of-the-art machine learning models, the random forest model emerged as the best classifier with 96.9% accuracy. All classifications received a probability score reflecting the confidence of the prediction. Increasing the score threshold improved the random forest classifier performance up to 100% with 87% of samples with scores surpassing the cutoff. Using a logistic regression model, detection of nonpancreatic neoplasms achieved an area under the curve of >0.99. Analysis of biopsy specimens showed concordant classification with their paired resection sample. CONCLUSIONS: Pancreatic neoplasms can be classified with high accuracy based on DNA methylation signatures. Additionally, non-pancreatic neoplasms are identified with near perfect precision. In summary, methylation profiling can serve as a valuable adjunct in the diagnosis of pancreatic neoplasms with minimal risk for misdiagnosis, even in the pre-operative setting.

Gastric Carcinoma in Autoimmune Gastritis: A Histopathologic and Molecular Study.

Patients with autoimmune gastritis (AIG) have a 13-fold risk of developing type-1 neuroendocrine tumors, whereas the risk for gastric adenocarcinoma is still uncertain. Here we describe the clinicopathologic and molecular features of a series of gastric carcinomas (GC) arising in the context of AIG. A total of 26 AIG-associated GC specimens were collected from 4 Italian Institutions. Immunohistochemistry for MUC1, MUC2, MUC5AC, MUC6, CDX2, HER2, PD-L1, CLDN18, mismatch repair (MMR) proteins, and p53 and EBV-encoded RNA (EBER) in situ hybridization were performed. Histologic and immunohistochemical features were jointly reviewed by 5 expert gastrointestinal pathologists. Next-generation sequencing analysis (TrueSight Oncology 500, Illumina) of 523 cancer-related genes was performed on 19 cases. Most tumors were diagnosed as pT1 (52%) and they were located in the corpus/fundus (58%) and associated with operative link for gastritis assessment stage II gastritis (80.8%), absence of parietal cells, complete intestinal metaplasia, and enterochromaffin-like-cell micronodular hyperplasia. Only 4 (15.4%) GCs were diagnosed during follow-up for AIG. The following histotypes were identified: 20 (77%) adenocarcinomas; 3 (11%) mixed neuroendocrine-non-neuroendocrine neoplasms, and 2 (8%) high-grade solid adenocarcinomas with focal neuroendocrine component, 1 (4%) adenocarcinoma with an amphicrine component. Overall, 7 cases (27%) showed MMR deficiency, 3 (12%) were positive (score 3+) for HER2, 6 (23%) were CLDN18 positive, and 11 (42%) had PD-L1 combined positive score ≥ 10. EBER was negative in all cases. Molecular analysis revealed 5/19 (26%) microsatellite instability (MSI) cases and 7 (37%) tumor mutational burden (TMB) high. The most frequently altered genes were TP53 (8/19, 42%), RNF43 (7/19, 37%), ERBB2 (7/19, 37% [2 amplified and 5 mutated cases]), ARID1A (6/19, 32%), and PIK3CA (4/19, 21%). In summary, AIG-associated GCs are often diagnosed at low stage in patients with longstanding misrecognized severe AIG; they often display a neuroendocrine component or differentiation, have relatively higher rates of MMR deficiency, and TMB high.

SWI/SNF Complex-Deficient Undifferentiated Carcinoma of the Pancreas: Clinicopathologic and Genomic Analysis.

Inactivating alterations in the SWItch/Sucrose NonFermentable (SWI/SNF) Chromatin Remodeling Complex subunits have been described in multiple tumor types. Recent studies focused on SMARC subunits of this complex to understand their relationship with tumor characteristics and therapeutic opportunities. To date, pancreatic cancer with these alterations has not been well studied, although isolated cases of undifferentiated carcinomas have been reported. Herein, we screened 59 pancreatic undifferentiated carcinomas for alterations in SWI/SNF complex-related (SMARCB1 [BAF47/INI1], SMARCA4 [BRG1], SMARCA2 [BRM]) proteins and/or genes using immunohistochemistry and/or next-generation sequencing. Cases with alterations in SWI/SNF complex-related proteins/genes were compared with cases without alterations, as well as with 96 conventional pancreatic ductal adenocarcinomas (PDAC). In all tumor groups, mismatch repair and PD-L1 protein expression were also evaluated. Thirty of 59 (51%) undifferentiated carcinomas had a loss of SWI/SNF complex-related protein expression or gene alteration. Twenty-seven of 30 (90%) SWI-/SNF-deficient undifferentiated carcinomas had rhabdoid morphology (vs 9/29 [31%] SWI-/SNF-retained undifferentiated carcinomas; P < .001) and all expressed cytokeratin, at least focally. Immunohistochemically, SMARCB1 protein expression was absent in 16/30 (53%) cases, SMARCA2 in 4/30 (13%), and SMARCA4 in 4/30 (13%); both SMARCB1 and SMARCA2 protein expressions were absent in 1/30 (3%). Five of 8 (62.5%) SWI-/SNF-deficient undifferentiated carcinomas that displayed loss of SMARCB1 protein expression by immunohistochemistry were found to have corresponding SMARCB1 deletions by next-generation sequencing. Analysis of canonical driver mutations for PDAC in these cases showed KRAS (2/5) and TP53 (2/5) abnormalities. Median combined positive score for PD-L1 (E1L3N) was significantly higher in the undifferentiated carcinomas with/without SWI/SNF deficiency compared with the conventional PDACs (P < .001). SWI-/SNF-deficient undifferentiated carcinomas were larger (P < .001) and occurred in younger patients (P < .001). Patients with SWI-/SNF-deficient undifferentiated carcinoma had worse overall survival compared with patients with SWI-/SNF-retained undifferentiated carcinoma (P = .004) and PDAC (P < .001). Our findings demonstrate that SWI-/SNF-deficient pancreatic undifferentiated carcinomas are frequently characterized by rhabdoid morphology, exhibit highly aggressive behavior, and have a negative prognostic impact. The ones with SMARCB1 deletions appear to be frequently KRAS wild type. Innovative developmental therapeutic strategies targeting this genomic basis of the SWI/SNF complex and the therapeutic implications of EZH2 inhibition (NCT03213665), SMARCA2 degrader (NCT05639751), or immunotherapy are currently under investigation.

Comprehensive Characterization of Intraductal Oncocytic Papillary Neoplasm of the Pancreas: A Systematic and Critical Review.

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a recently recognized pancreatic tumor. Here, we aimed to determine its most essential features with the systematic review tool. PubMed, Scopus, and Embase were searched for studies reporting data on pancreatic IOPN. The clinicopathologic, immunohistochemical, and molecular data were extracted and summarized. Then, a comparative analysis of the molecular alterations of IOPN with those of pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm from reference cohorts (including The Cancer Genome Atlas) was conducted. The key findings from 414 IOPNs were as follows: 1) The male-to-female ratio was 1.5:1. Pancreatic head was the most common site (131/237; 55.3%), but a diffuse tumor extension involving more than one pancreatic segment was described in about 1 out of 5 cases (49/237; 20.6%). The mean size was 45.5 mm. An associated invasive carcinoma was present in 50% of cases (168/336). In those cases, most tumors were pT1 or pT2 and pN0 (>80%), and vascular invasion was uncommon (20.6%). Regarding survival, more than 90% of patients were alive after surgical resection. 2) Immunohistochemical and molecular features were as follows. The most commonly expressed mucins were MUC5AC (110/112; 98.2%) and MUC6 (78/84; 92.8%). Compared with pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm, the classic pancreatic drivers KRAS, TP53, CDKN2A, SMAD4, and GNAS were less altered in IOPN (P < .01). Moreover, fusions involving PRKACA or PRKACB gene were detected in all of the 68 cases examined, with PRKACB::ATP1B1 being the most common (27/68 cases; 39.7%). These genomic events emerged as an entity-defining molecular alteration of IOPN (P < .01). Thus, such fusions represent a promising biomarker for diagnostic purposes. Recent evidence also suggests their role in influencing the acquisition of oncocytic morphology. IOPN is a distinct pancreatic neoplasm with specific clinicopathologic and molecular features. Considering the clinical or prognostic implications, its recognition is essential for pathologists and, ultimately, patients' management.

Subgrading of G2 Pancreatic Neuroendocrine Tumors as 2A (Ki67 3% to < 10%) Versus 2B (10% to ≤ 20%) Identifies Behaviorally Distinct Subsets in Keeping with the Evolving Management Protocols.

BACKGROUND: Grade 1/2 PanNETs are mostly managed similarly, typically without any adjunct treatment with the belief that their overall metastasis rate is low. In oncology literature, Ki67-index of 10% is increasingly being used as the cutoff in stratifying patients to different protocols, although there are no systematic pathology-based studies supporting this approach. METHODS: Ki67-index was correlated with clinicopathologic parameters in 190 resected PanNETs. A validation cohort (n = 145) was separately analyzed. RESULTS: In initial cohort, maximally selected rank statistics method revealed 12% to be the discriminatory cutoff (close to 10% rule of thumb). G2b cases had liver/distant metastasis rate of almost threefold higher than that of G2a and showed significantly higher frequency of all histopathologic signs of aggressiveness (tumor size, perineural/vascular invasion, infiltrative growth pattern, lymph node metastasis). In validation cohort, these figures were as striking. When all cases were analyzed together, compared with G1, the G2b category had nine times higher liver/distant metastasis rate (6.1 vs. 58.5%; p < 0.001) and three times higher lymph node metastasis rate (20.5 vs. 65.1%; p < 0.001). CONCLUSIONS: G2b PanNETs act very similar to G3, supporting management protocols that regard them as potential therapy candidates. Concerning local management, metastatic behavior in G2b cases indicate they may not be as amenable for conservative approaches, such as watchful waiting or enucleation. This substaging should be considered into diagnostic guidelines, and clinical trials need to be devised to determine the more appropriate management protocols for G2b (10% to ≤ 20%) group, which shows liver/distant metastasis in more than half of the cases, which at minimum warrants closer follow-up.

Efficacy and Toxicity Analysis of mFOLFIRINOX in High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms.

BACKGROUND: High-grade neuroendocrine neoplasms (NENs) comprise both well-differentiated grade 3 neuroendocrine tumors (G3 NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) nearly always include poorly differentiated NEC as the neuroendocrine component. The efficacy and safety of frontline mFOLFIRINOX chemotherapy has never been investigated in patients with high-grade NENs. PATIENTS AND METHODS: We conducted a multi-institutional retrospective analysis of patients with advanced high-grade NEN of the gastroenteropancreatic tract or of unknown origin seen between February 2016 and April 2023 who received treatment with frontline mFOLFIRINOX. RESULTS: A total of 35 patients were included (G3 NETs: n=2; NECs: n=25; MiNENs: n=8; stage III: n=5; stage IV: n=30). The objective response rate was 77% (complete response: 3%; partial response: 74%). Median progression-free survival was 12 months (95% CI, 9.2-16.2 months) and median overall survival was 20.6 months (95% CI, 17.2-30.6 months). No significant differences in efficacy were seen according to primary site, histopathology, and Ki-67 proliferative index. All 5 patients with stage III disease who received mFOLFIRINOX obtained an objective response and underwent radical surgery or definitive radiotherapy with curative intent, with a recurrence rate of 40%. Grade 3 or 4 adverse events were observed in 43% of patients (mainly neutropenia and diarrhea). Females were at significantly increased risk of developing severe toxicities. CONCLUSIONS: mFOLFIRINOX shows antitumor activity against high-grade NENs. Well-designed, prospective clinical trials are needed to assess the efficacy of mFOLFIRINOX in both the neoadjuvant and metastatic settings.

Either High or Low Risk: The Acinar Score at the Resection Margin Dichotomizes the Risk Spectrum of Pancreas-specific Complications After Pancreatoduodenectomy.

BACKGROUND: Pancreatic acinar content (Ac) has been associated with pancreas-specific complications after pancreatoduodenectomy. The aim of this study was to improve the prediction ability of intraoperative risk stratification by integrating the pancreatic acinar score. METHODS: A training and validation cohort underwent pancreatoduodenectomy with a subsequent histologic assessment of pancreatic section margins for Ac, fibrosis (Fc), and fat. Intraoperative risk stratification (pancreatic texture, duct diameter) and pancreas-specific complications (postoperative hyperamylasemia [POH], postpancreatectomy acute pancreatitis [PPAP], pancreatic fistula [POPF]) were classified according to ISGPS definitions. RESULTS: In the validation cohort (n= 373), the association of pancreas-specific complications with higher Ac and lower Fc was replicated (all P <0.001). In the entire cohort (n= 761), the ISGPS classification allocated 275 (36%) patients into intermediate-risk classes B (POH 32%/PPAP 3%/POPF 17%) and C (POH 36%/PPAP 9%/POPF 33%). Using the acinar score (Ac ≥60% and/or Fc ≤10%), intermediate-risk patients could be dichotomized into a low-risk (POH 5%/PPAP 1%/POPF 6%) and a high-risk (POH 51%/PPAP 9%/POPF 38%) group (all P <0.001). The acinar score AUC for POPF prediction was 0.70 in the ISGPS intermediate-risk classes. Overall, 239 (31%) patients were relocated into the high-risk group from lower ISGPS risk classes using the acinar score. CONCLUSIONS: The risk of pancreas-specific complications appears to be dichotomous-either high or low-according to the acinar score, a tool to better target the application of mitigation strategies in cases of intermediate macroscopic features.

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.

CA19.9 Response and Tumor Size Predict Recurrence Following Post-neoadjuvant Pancreatectomy in Initially Resectable and Borderline Resectable Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Data on recurrence after post-neoadjuvant pancreatectomy are scant. This study investigated the incidence and pattern of recurrence in patients with initially resectable and borderline resectable pancreatic ductal adenocarcinoma who received post-neoadjuvant pancreatectomy. Furthermore, preoperative predictors of recurrence-free survival (RFS) and their interactions were determined. PATIENTS AND METHODS: Patients undergoing post-neoadjuvant pancreatectomy at two academic facilities between 2013 and 2017 were analyzed using standard statistics. The possible interplay between preoperative parameters was scrutinized including interaction terms in multivariable Cox models. RESULTS: Among 315 included patients, 152 (48.3%) were anatomically resectable. The median RFS was 15.7 months, with 1- and 3-year recurrence rates of 41.9% and 74.2%, respectively. Distant recurrence occurred in 83.3% of patients, with lung-only patterns exhibiting the most favorable prognostic outlook. Normal posttreatment CA19.9, ΔCA19.9 (both in patients with normal and elevated baseline levels), and posttreatment tumor size were associated with RFS. Critical thresholds for ΔCA19.9 and tumor size were set at 50% and 20 mm, respectively. Interaction between ΔCA19.9 and posttreatment CA19.9 suggested a significant risk reduction in patients with elevated values when ΔCA19.9 exceeded 50%. Moreover, posttreatment tumor size interacted with posttreatment CA19.9 and ΔCA19.9, suggesting an increased risk in the instance of elevated posttreatment CA19.9 values and a protective effect associated with CA19.9 response in patients with tumor size >20 mm. CONCLUSION: Recurrence following post-neoadjuvant pancreatectomy is common. Preoperative tumor size <20 mm, normal posttreatment CA19.9 and ΔCA19.9 > 50% were associated with longer RFS. These variables should not be taken in isolation, as their interaction significantly modulates the recurrence risk.

Pathological staging in postneoadjuvant pancreatectomy for pancreatic cancer: implications for adjuvant therapy.

BACKGROUND: It is unclear whether pathological staging is significant prognostically and can inform the delivery of adjuvant therapy after pancreatectomy preceded by neoadjuvant therapy. METHODS: This multicentre retrospective study included patients who underwent pancreatectomy for pancreatic ductal adenocarcinoma after neoadjuvant treatment at two Italian centres between 2013 and 2017. T and N status were assigned in accordance with the seventh and eighth editions of the AJCC staging system, as well as according to a modified system with T status definition combining extrapancreatic invasion and tumour size. Patients were then stratified by receipt of adjuvant therapy. Survival analysis and multivariable interaction analysis of adjuvant therapy with pathological parameters were performed. The results were validated in an external cohort from the USA. RESULTS: The developmental set consisted of 389 patients, with a median survival of 34.6 months. The modified staging system displayed the best prognostic stratification and the highest discrimination (C-index 0.763; 1-, 2- and 3-year time-dependent area under the curve (AUC) 0.746, 0.722, and 0.705; Uno's AUC 0.710). Overall, 67.0 per cent of patients received adjuvant therapy. There was no survival difference by receipt of adjuvant therapy (35.0 versus 36.0 months; P = 0.772). After multivariable adjustment, interaction analysis suggested a benefit of adjuvant therapy for patients with nodal metastases or with tumours larger than 2 cm with extrapancreatic extension, regardless of nodal status. These results were confirmed in the external cohort of 216 patients. CONCLUSION: Modified staging with a T status definition combining extrapancreatic invasion and tumour size is associated with better prognostic segregation after postneoadjuvant pancreatectomy. This system allows identification of patients who might benefit from adjuvant therapy.

Systematic review of challenging issues in pathology of intraductal papillary mucinous neoplasms.

BACKGROUND: Intraductal papillary mucinous neoplasms (IPMNs) are a cystic precursor to pancreatic cancer. IPMNs deemed clinically to be at high-risk for malignant progression are frequently treated with surgical resection, and pathological examination of the pancreatectomy specimen is a key component of the clinical care of IPMN patients. METHODS: Systematic literature reviews were conducted around eight topics of clinical relevance in the examination of pathological specimens in patients undergoing resection of IPMN. RESULTS: This review provides updated perspectives on morphological subtyping of IPMNs, classification of intraductal oncocytic papillary neoplasms, nomenclature for high-grade dysplasia, assessment of T stage, distinction of carcinoma associated or concomitant with IPMN, role of molecular assessment of IPMN tissue, role of intraoperative assessment by frozen section, and preoperative evaluation of cyst fluid cytology. CONCLUSIONS: This analysis provides the foundation for data-driven approaches to several challenging issues in the pathology of IPMNs.

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.

Histopathological Landscape of Precursor Lesions of Gastro-Entero-Pancreatic Neuroendocrine Neoplasms.

BACKGROUND: Despite the important advances in research on neuroendocrine neoplasms of the gastro-entero-pancreatic tract, their precursor lesions are much less well known. SUMMARY: This review analyzes the preneoplastic neuroendocrine lesions of the gastro-entero-pancreatic tract, by adopting a coherent anatomical benchmark. In particular, the settings in which neuroendocrine precursor lesions represent well-recognized pathophysiological and morphological entities (with eventual molecular correlates) have been distinguished from the ones in which the nature of preneoplastic changes is still obscure. KEY MESSAGES: The aim of the paper was to summarize what is known about precursor lesions of gastro-entero-pancreatic neuroendocrine tumors, with the goal of providing a useful tool for future research aimed at obtaining a fuller understanding of the underlying biology and early development of these diseases.

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.

Artificial intelligence in oncology: current applications and future perspectives.

Artificial intelligence (AI) is concretely reshaping the landscape and horizons of oncology, opening new important opportunities for improving the management of cancer patients. Analysing the AI-based devices that have already obtained the official approval by the Federal Drug Administration (FDA), here we show that cancer diagnostics is the oncology-related area in which AI is already entered with the largest impact into clinical practice. Furthermore, breast, lung and prostate cancers represent the specific cancer types that now are experiencing more advantages from AI-based devices. The future perspectives of AI in oncology are discussed: the creation of multidisciplinary platforms, the comprehension of the importance of all neoplasms, including rare tumours and the continuous support for guaranteeing its growth represent in this time the most important challenges for finalising the 'AI-revolution' in oncology.

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."

High-risk Pancreatic Anastomosis Versus Total Pancreatectomy After Pancreatoduodenectomy: Postoperative Outcomes and Quality of Life Analysis.

OBJECTIVE: To evaluate TP as an alternative to PD in patients at high-risk for popf. BACKGROUND: Outcomes of high-risk PD (HR-PD) and TP have never been compared. METHODS: All patients who underwent PD or TP between July 2017 and December 2019 were identified. HR-PD was defined according to the alternative fistula risk score. Postoperative outcomes (primary endpoint), pancreatic insufficiency, and quality of life after 12 months of follow-up (QoL) were compared between HR-PD or planned PD intraoperatively converted to TP (C-TP). RESULTS: A total of 566 patients underwent PD and 136 underwent TP during the study period. One hundred one (18%) PD patients underwent HR-PD, whereas 86 (63%) TP patients underwent C-TP. Postoperatively, the patients in the C-TP group exhibited lower rates of postpancreatectomy hemorrhage (15% vs 28%), delayed gastric emptying (16% vs 34%), sepsis (10% vs 31%), and Clavien-Dindo ≥3 morbidity (19% vs 31%) and had shorter median lengths of hospital stay (10 vs 21 days) (all P < 0.05). The rate of POPF in the HR-PD group was 39%. Mortality was comparable between the 2 groups (3% vs 4%). Although general, cancer- and pancreas-specific QoL were comparable between the HR-PD and C-TP groups, endocrine and exocrine insufficiency occurred in all the C-TP patients, compared to only 13% and 63% of the HR-PD patients, respectively, and C-TP patients had worse diabetesspecific QoL. CONCLUSIONS: C-TP may be considered rather than HR-PD only in few selected cases and after adequate counseling.

Reassessment of the Optimal Number of Examined Lymph Nodes in Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma.

OBJECTIVE: The aim of this study was to reappraise the optimal number of examined lymph nodes (ELNs) in pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC). SUMMARY BACKGROUND DATA: The well-established threshold of 15 ELNs in PD for PDAC is optimized for detecting 1 positive node (PLN) per the previous 7th edition of the American Joint Committee on Cancer (AJCC) staging manual. In the framework of the 8th edition, where at least 4 PLN are needed for an N2 diagnosis, this threshold may be inadequate for accurate staging. METHODS: Patients who underwent upfront PD at 2 academic institutions between 2000 and 2016 were analyzed. The optimal ELN threshold was defined as the cut-point associated with a 95% probability of identifying at least 4 PLNs in N2 patients. The results were validated addressing the N-status distribution and stage migration. RESULTS: Overall, 1218 patients were included. The median number of ELN was 26 (IQR 17-37). ELN was independently associated with N2-status (OR 1.27, P < 0.001). The estimated optimal threshold of ELN was 28. This cut-point enabled improved detection of N2 patients and stage III disease (58% vs 37%, P = 0.001). The median survival was 28.6 months. There was an improved survival in N0/N1 patients when ELN exceeded 28, suggesting a stage migration effect (47 vs 29 months, adjusted HR 0.649, P < 0.001). In N2 patients, this threshold was not associated with survival on multivariable analysis. CONCLUSION: Examining at least 28 LN in PD for PDAC ensures optimal staging through improved detection of N2/stage III disease. This may have relevant implications for benchmarking processes and quality implementation.