Computed Tomography-Based Radiomics with Machine Learning Outperforms Radiologist Assessment in Estimating Colorectal Liver Metastases Pathologic Response After Chemotherapy.

OBJECTIVES: This study was designed to assess computed tomography (CT)-based radiomics of colorectal liver metastases (CRLM), extracted from posttreatment scans in estimating pathologic treatment response to neoadjuvant therapy, and to compare treatment response estimates between CT-based radiomics and radiological response assessment by using RECIST 1.1 and CT morphologic criteria. METHODS: Patients who underwent resection for CRLM from January 2003-December 2012 at a single institution were included. Patients who did not receive preoperative systemic chemotherapy, or without adequate imaging, were excluded. Imaging characteristics were evaluated based on RECIST 1.1 and CT morphologic criteria. A machine-learning model was designed with radiomic features extracted from manually segmented posttreatment CT tumoral and peritumoral regions to identify pathologic responders (≥ 50% response) versus nonresponders. Statistical analysis was performed at the tumor level. RESULTS: Eighty-five patients (median age, 62 years; 55 women) with 95 tumors were included. None of the subjectively evaluated imaging characteristics were associated with pathologic response (p > 0.05). Inter-reader agreement was substantial for RECIST categorical response assessment (K = 0.70) and moderate for CT morphological group response (K = 0.50). In the validation cohort, the machine learning model built with radiomic features obtained an area under the curve (AUC) of 0.87 and outperformed subjective RECIST assessment (AUC = 0.53, p = 0.01) and morphologic assessment (AUC = 0.56, p = 0.02). CONCLUSIONS: Radiologist assessment of oligometastatic CRLM after neoadjuvant therapy using RECIST 1.1 and CT morphologic criteria was not associated with pathologic response. In contrast, a machine-learning model based on radiomic features extracted from tumoral and peritumoral regions had high diagnostic performance in assessing responders versus nonresponders.

Failure to Rescue After Resection of Perhilar Cholangiocarcinoma in an International Multicenter Cohort.

BACKGROUND: Failure to rescue (FTR) is defined as the inability to prevent death after the development of a complication. FTR is a parameter in evaluating multidisciplinary postoperative complication management. The aim of this study was to evaluate FTR rates after major liver resection for perihilar cholangiocarcinoma (pCCA) and analyze factors associated with FTR. PATIENTS AND METHOD: Patients who underwent major liver resection for pCCA at 27 centers were included. FTR was defined as the presence of a Dindo grade III or higher complication followed by death within 90 days after surgery. Liver failure ISGLS grade B/C were scored. Multivariable logistic analysis was performed to identify predictors of FTR and reported using odds ratio and 95% confidence intervals. RESULTS: In the 2186 included patients, major morbidity rate was 49%, 90-day mortality rate 13%, and FTR occurred in 24% of patients with a grade III or higher complication. Across centers, major complication rate varied from 19 to 87%, 90-day mortality rate from 5 to 33%, and FTR ranged from 11 to 50% across hospitals. Age [1.04 (1.02-1.05) years], ASA 3 or 4 [1.40 (1.01-1.95)], jaundice at presentation [1.79 (1.16-2.76)], right-sided resection [1.45 (1.06-1.98)], and annual hospital volume < 6 [1.44 (1.07-1.94)] were positively associated with FTR. When liver failure is included, the odds ratio for FTR is 9.58 (6.76-13.68). CONCLUSION: FTR occurred in 24% of patients after resection for pCCA. Liver failure was associated with a nine-fold increase of FTR and hospital volume below six was also associated with an increased risk of FTR.

Initiation of a robotic pancreatoduodenectomy program using virtual collaboration.

BACKGROUND: Adoption of robotic pancreatoduodenectomy (RPD) is growing, although there are challenges for safe introduction of this technique, including limitations in on-site expert proctoring. We developed and implemented a structured approach for safe introduction of a new RPD program using virtual collaboration. METHODS: A structured framework for introducing a RPD program was designed; key steps included obtaining additional training, identifying required resources, establishing a dedicated team, and patient safety considerations. Virtual collaboration with a proctor for bidirectional communication was utilized for remote operative guidance. In the initial cohort, perioperative data and postoperative outcomes were extracted from a prospectively maintained database. RESULTS: From August 2020 to December 2023, 68 patients underwent RPD. The median operative time was 407 min with an estimated blood loss of 150 mL. Median length of stay was 8 days. Negative margins were obtained in 90% of resections. Operative time was significantly shorter in the second half of cases compared to the first (380min vs 441min, p < 0.01) and rate of conversion decreased (6% vs 21%). CONCLUSION: The safe initiation of a structured RPD program is feasible through virtual expert collaboration. With careful consideration and an appropriate environment, excellent perioperative outcomes are achievable even for initial cases.

Long term outcomes in patients with advanced intrahepatic cholangiocarcinoma treated with hepatic arterial infusion chemotherapy.

INTRODUCTION: Hepatic artery infusion (HAI) of chemotherapy has demonstrated disease control and suggested improvement in overall survival (OS) in intrahepatic cholangiocarcinoma (IHC). We report herein the long-term results and role of molecular alterations of a phase II clinical trial of HAI chemotherapy plus systemic chemotherapy, with a retrospective cohort of patients treated with HAI at Memorial Sloan Kettering Cancer Center. METHODS: This secondary analysis of a single-institution, phase 2 trial and retrospective cohort of unresectable IHC treated with HAI floxuridine (FUDR) plus systemic gemcitabine and oxaliplatin. The primary aim was to assess long-term oncologic outcomes. A subset underwent tissue-based genomic sequencing, and molecular alterations were correlated with progression-free survival (PFS) and OS. RESULTS: Thirty-eight patients were treated on trial with a median follow up of 76.9 months. Median PFS was 11.8 months (95% CI11-15.1). The median OS was 26.8 months (95% CI20.9-40.6). The 1-, 2- and 5-year OS rate was 89.5%, 55%, and 21% respectively. Nine (24%) received HAI with mitomycin C post FUDR progression with an objective response rate of 44% and a median PFS of 3.93 (2.33-NR) months. One-hundred and seventy patients not treated on the clinical trial were included in a retrospective analysis. Median PFS and OS was 7.93 (95%CI: 7.27-10.07) and 22.5 (95%CI : 19.5-28.3) months, respectively. Alterations in the TP53 and cell-cycle pathway had a worse PFS to HAI based therapy compared to wildtype disease. CONCLUSION: In locally advanced IHC, HAI with FUDR in combination with systemic therapy can offer long term durable disease control. Molecular alterations may predict for response.

Conversion Therapy to Transplant or Surgical Resection in Patients with Unresectable Hepatocellular Carcinoma Treated with Boosted Dose of Yttrium-90 Radiation Segmentectomy.

BACKGROUND/OBJECTIVES: The aim of this study was to assess the efficacy of boosted dose yttrium-90 radioembolization (TARE) as a modality for conversion therapy to transplant or surgical resection in patients with unresectable hepatocellular carcinoma (HCC). METHODS: In this single-center retrospective study, all patients with a diagnosis of HCC who were treated with boosted dose TARE (>190 Gy) between January 2013 and December 2023 were reviewed. Treatment response and decrease in tumor size were assessed with the RECIST v1.1 and mRECIST criteria. Milan and University of California, San Francisco (UCSF), criteria were used to determine transplant eligibility, and Barcelona Clinic Liver Cancer (BCLC) surgical resection recommendations were used to evaluate tumor resectability. RESULTS: Thirty-eight patients with primary HCC who were treated with boosted dose TARE were retrospectively analyzed. The majority of the patients were Child-Pugh A (n = 35; 92.1%), BCLC C (n = 17; 44.7%), and ECOG performance status 0 (n = 25; 65.8%). The mean sum of the target lesions was 6.0 cm (standard deviation; SD = 4.0). The objective response rate (ORR) was 31.6% by RECIST and 84.2% by mRECIST. The disease control rate (DCR) was 94.7% by both RECIST and mRECIST. Among patients outside of Milan or UCSF, 13/25 (52.0%, Milan) and 9/19 (47.4%, UCSF) patients were successfully converted to within transplant criteria. Of patients who were initially unresectable, conversion was successful in 7/26 (26.9%) patients. CONCLUSIONS: This study provides further real-world data demonstrating that boosted-dose TARE is an effective modality for conversion of patients with unresectable HCC to transplant or resection.

Genome-Derived Ampullary Adenocarcinoma Classifier and Postresection Prognostication.

Importance: Ampullary adenocarcinoma (AA) is characterized by clinical and genomic heterogeneity. A previously developed genomic classifier defined biologically distinct phenotypes with greater accuracy than standard histologic classification. External validation is needed before routine clinical use. Objective: To test external validity of the prognostic value of the hidden genome classifier of AA. Design, Setting, and Participants: This retrospective cohort study took place at 6 international academic institutions. Consecutive patients (n = 192) who underwent curative-intent resection of histologically confirmed AA were included. The data were analyzed from January 2005 through July 2020. Exposures: The multilevel meta-feature regression model previously trained on a prospectively sequenced cohort of 3411 patients (1001 pancreatic adenocarcinoma, 165 distal bile duct adenocarcinoma, and 2245 colorectal adenocarcinoma) was applied to AA sequencing data to quantify the relative proportions of parental cell of origin. Main Outcome and Measures: Genomic classification was correlated with immunohistologic subtype (intestinal [INT] or pancreatobiliary [PB]) and with overall survival (OS), using the log-rank test and Cox proportional hazard models. Results: Among 192 patients with AA (median age, 69.0 [IQR, 60.0-74.0] years and 134 were male [64%]), concordance between immunohistologic and genomic subtypes was 55%. Most INT subtype tumors were categorized into the colorectal genomic subtype (43 of 57 [72.9%]). Of the 114 PB subtype tumors, 29 had a pancreatic genomic profile (25.4%) and 24 had a distal bile duct genomic profile (21.1%). Whereas the standard immunohistologic subtypes were not associated with survival (log rank P = .26), predicted genomic probabilities were correlated with survival probability. Genomic scores with higher colorectal probability were associated with higher survival probability; higher pancreatic and distal bile duct probabilities were associated with lower survival probability. Conclusions and Relevance: The AA genomic classifier is reproducible with available molecular testing in a diverse international cohort of patients and improves stratification of the divergent clinical outcomes beyond standard immunohistologic classification. These data provide a molecular classification that may be incorporated into clinical trials for prospective validation.

Distinct clinical outcomes and biological features of specific KRAS mutants in human pancreatic cancer.

KRAS mutations in pancreatic ductal adenocarcinoma (PDAC) are suggested to vary in oncogenicity but the implications for human patients have not been explored in depth. We examined 1,360 consecutive PDAC patients undergoing surgical resection and find that KRASG12R mutations are enriched in early-stage (stage I) disease, owing not to smaller tumor size but increased node-negativity. KRASG12R tumors are associated with decreased distant recurrence and improved survival as compared to KRASG12D. To understand the biological underpinnings, we performed spatial profiling of 20 patients and bulk RNA-sequencing of 100 tumors, finding enhanced oncogenic signaling and epithelial-mesenchymal transition (EMT) in KRASG12D and increased nuclear factor κB (NF-κB) signaling in KRASG12R tumors. Orthogonal studies of mouse KrasG12R PDAC organoids show decreased migration and improved survival in orthotopic models. KRAS alterations in PDAC are thus associated with distinct presentation, clinical outcomes, and biological behavior, highlighting the prognostic value of mutational analysis and the importance of articulating mutation-specific PDAC biology.

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.

'IHPBA-APHPBA clinical practice guidelines': international Delphi consensus recommendations for gallbladder cancer.

BACKGROUND: The Delphi consensus study was carried out under the auspices of the International and Asia-Pacific Hepato-Pancreato-Biliary Associations (IHPBA-APHPBA) to develop practice guidelines for management of gallbladder cancer (GBC) globally. METHOD: GBC experts from 17 countries, spanning 6 continents, participated in a hybrid four-round Delphi consensus development process. The methodology involved email, online consultations, and in-person discussions. Sixty eight clinical questions (CQs) covering various domains related to GBC, were administered to the experts. A consensus recommendation was accepted only when endorsed by more than 75% of the participating experts. RESULTS: Out of the sixty experts invited initially to participate in the consensus process 45 (75%) responded to the invitation. The consensus was achieved in 92.6% (63/68) of the CQs. Consensus covers epidemiological aspects of GBC, early, incidental and advanced GBC management, definitions for radical GBC resections, the extent of liver resection, lymph node dissection, and definitions of borderline resectable and locally advanced GBC. CONCLUSIONS: This is the first international Delphi consensus on GBC. These recommendations provide uniform terminology and practical clinical guidelines on the current management of GBC. Unresolved contentious issues like borderline resectable/locally advanced GBC need to be addressed by future clinical studies.

Extrahepatic Cholangiocarcinoma: Genomic Variables Associated With Anatomic Location and Outcome.

PURPOSE: This study aimed to define genomic differences between perihilar cholangiocarcinoma (PCA) and distal cholangiocarcinoma (DCA) and identify genomic determinants of survival. MATERIALS AND METHODS: Consecutive patients with ECA with tissue for targeted next-generation sequencing were analyzed, stratified by anatomic site (PCA/DCA), disease extent, and treatment. Associations between genomic alterations, clinicopathologic features, and outcomes were analyzed using Cox proportional hazards regression to compare survival. RESULTS: In total, 224 patients diagnosed between 2004 and 2022 (n = 127 PCA; n = 97 DCA) met inclusion criteria. The median survival was 29 months (43 after resection and 17 from diagnosis for unresectable disease). Compared with PCA, DCA was enriched in TP53alt (alterations; 69% v 33%; Q < 0.01), epigenetic pathway alterations (45% v 29%; Q = 0.041), and had more total altered pathways (median 3 v 2; Q < 0.01). KRASalt frequency was similar between PCA (36%) and DCA (37%); however, DCA was enriched in KRAS G12D (19% v 9%; P = .002). No other clinicopathologic or genomic variables distinguished subtypes. In resected patients, no genomic alterations were associated with outcome. However, in unresectable patients, CDKN2Aalt (hazard ratio [HR], 2.59 [1.48 to 4.52]) and APCalt (HR, 5.11 [1.96 to 13.3]) were associated with reduced survival. For the entire cohort, irresectability (HR, 3.13 [2.25 to 4.36]), CDKN2Aalt (HR, 1.80 [1.80 to 2.68]), and APCalt (HR, 2.00 [1.04 to 3.87]) were associated with poor survival. CONCLUSION: CDKN2Aalt and APCalt were associated with poor survival in ECA, primarily in advanced disease. As PCA and DCA were genetically similar, coanalysis of PCA and DCA in future genomic studies is reasonable.

Optimization of ultracentrifugation-based method to enhance the purity and proteomic profiling depth of plasma-derived extracellular vesicles and particles.

Circulating extracellular vesicles and particles (EVPs) are being investigated as potential biomarkers for early cancer detection, prognosis, and disease monitoring. However, the suboptimal purity of EVPs isolated from peripheral blood plasma has posed a challenge of in-depth analysis of the EVP proteome. Here, we compared the effectiveness of different methods for isolating EVPs from healthy donor plasma, including ultracentrifugation (UC)-based protocols, phosphatidylserine-Tim4 interaction-based affinity capture (referred to as "PS"), and several commercial kits. Modified UC methods with an additional UC washing or size exclusion chromatography step substantially improved EVP purity and enabled the detection of additional proteins via proteomic mass spectrometry, including many plasma membrane and cytoplasmic proteins involved in vesicular regulation pathways. This improved performance was reproduced in cancer patient plasma specimens, resulting in the identification of a greater number of differentially expressed EVP proteins, thus expanding the range of potential biomarker candidates. However, PS and other commercial kits did not outperform UC-based methods in improving plasma EVP purity. PS yielded abundant contaminating proteins and a biased enrichment for specific EVP subsets, thus unsuitable for proteomic profiling of plasma EVPs. Therefore, we have optimized UC-based protocols for circulating EVP isolation, which enable further in-depth proteomic analysis for biomarker discovery.

Has Management of Intrahepatic Cholangiocarcinoma Evolved with the Evidence? Trends and Practice Patterns from the National Cancer Database.

BACKGROUND: Management of intrahepatic cholangiocarcinoma (IHC) has advanced in recent decades, including randomized trial evidence supporting systemic therapy in the palliative and adjuvant setting. Mounting observational evidence suggests resection of IHC with multifocal disease (IHC-MF) or lymph node metastasis (IHC-LNM) should be limited. It is unknown how real-world practice has evolved in light of research advances. This study characterizes trends in management and outcomes of IHC without distant metastasis. METHODS: We queried the National Cancer Database (NCDB) for patients treated for IHC without distant metastasis (M0) and identified subgroups with lymph node (cN1) or multifocal hepatic involvement (cT2b). Two-sided Cochran-Armitage tests evaluated trends in initial treating modality and perioperative chemotherapy. Logistic regression evaluated associations with choice of initial treating modality. Overall survival (OS) was evaluated by using Kaplan-Meier methods. RESULTS: Between 2004 and 2020, 11,368 patients were treated for IHC without extrahepatic metastasis. Forty-three percent underwent resection. Initial management shifted from resection towards radiation or systemic therapy in IHC-MF and IHC-LNM. Use of perioperative chemotherapy increased from 39% pre-2010 to 70% in 2018-2020 (p < 0.001), most often delivered postoperatively. Across the entire cohort, median OS improved from 16 (95% confidence interval [CI] 15-18) to 27 months (95% CI 26-29). More modest improvements were observed in IHC-MF and IHC-LNM. CONCLUSIONS: Use of perioperative chemotherapy has been widely adopted, predating randomized trial evidence in the adjuvant setting. Initial management of IHC-MF and IHC-LNM has shifted from resection to systemic and/or radiation therapy. While OS has improved overall, outcomes of IHC-MF and IHC-LNM remain poor, warranting further investigation.

Safety of Selective Operative Drainage After Pancreatic Resection: A Retrospective Analysis of 2,607 Patients.

OBJECTIVE: To assess whether selective omission of operative drains after pancreaticoduodenectomy (PD) and distal pancreatectomy (DP) is associated with adverse perioperative outcomes. BACKGROUND: The routine use of operative drains after pancreatectomy is widely practiced; however, prospective randomized clinical trials and retrospective analyses have shown mixed results. METHODS: Patients who underwent PD or DP between November 2009 and May 2021 were reviewed and stratified by operative drain placement. Patient demographics, morbidity, the need for additional procedures, and mortality were compared between patients who did or did not develop a clinically relevant post-operative pancreatic fistula (CR-POPF). RESULTS: In total, 1,855 PD and 752 DP cases were analyzed. Among PD patients with a CR-POPF (N=259, 14%), 160 (62%) had an operative drain placed, of whom 141 (88%) required at least 1 additional procedure. Within this subgroup, grade ≥ 4 complications (7.5% vs. 11.1%, P=0.37), 90-day mortality (3.8% vs. 6.1%, P=0.54), length of stay (LOS) (median 12 vs. 13 d, P=0.19) and readmission rates (63.1% vs. 54.6%, P=0.19) were similar between drained and non-drained patients. Of note, drained PD patients without a CR-POPF had a longer hospital stay (8 vs. 7 d, respectively, P=0.004) and more thromboembolic events (2.4% vs. 1.1%, respectively, P=0.04) Among DP patients with a CR-POPF (n=129), 44 had an operative drain, with 37 (84%) requiring an additional procedure. Within this subgroup, grade ≥ 4 complications (4.6% vs. 5.9%, P>0.95), 90-day mortality (0%), LOS (median 7 d for both, P=0.88) and readmission rates (72.7% vs. 80%, P=0.38) were similar in drained and non-drained patients. CONCLUSION: This study confirms that selective omission of operative drains does not compromise perioperative outcomes, as initially reported in our prospective randomized trial.

Comparing regularized Kelvinlet functions and the finite element method for registration of medical images to sparse organ data.

Image-guided surgery collocates patient-specific data with the physical environment to facilitate surgical decision making. Unfortunately, these guidance systems commonly become compromised by intraoperative soft-tissue deformations. Nonrigid image-to-physical registration methods have been proposed to compensate for deformations, but clinical utility requires compatibility of these techniques with data sparsity and temporal constraints in the operating room. While finite element models can be effective in sparse data scenarios, computation time remains a limitation to widespread deployment. This paper proposes a registration algorithm that uses regularized Kelvinlets, which are analytical solutions to linear elasticity in an infinite domain, to overcome these barriers. This algorithm is demonstrated and compared to finite element-based registration on two datasets: a phantom liver deformation dataset and an in vivo breast deformation dataset. The regularized Kelvinlets algorithm resulted in a significant reduction in computation time compared to the finite element method. Accuracy as evaluated by target registration error was comparable between methods. Average target registration errors were 4.6 ± 1.0 and 3.2 ± 0.8 mm on the liver dataset and 5.4 ± 1.4 and 6.4 ± 1.5 mm on the breast dataset for the regularized Kelvinlets and finite element method, respectively. Limitations of regularized Kelvinlets include the lack of organ-specific geometry and the assumptions of linear elasticity and infinitesimal strain. Despite limitations, this work demonstrates the generalizability of regularized Kelvinlets registration on two soft-tissue elastic organs. This method may improve and accelerate registration for image-guided surgery, and it shows the potential of using regularized Kelvinlets on medical imaging data.

Clinicogenomic predictors of outcomes in patients with hepatocellular carcinoma treated with immunotherapy.

INTRODUCTION: Immune checkpoint inhibitor (ICI) combinations extend overall survival (OS) while anti-PD-1/L1 monotherapy is non-inferior to sorafenib in treatment-naïve, patients with advanced hepatocellular carcinoma (HCC). Clinicogenomic features are posited to influence patient outcomes. METHODS: The primary objective of this retrospective study was to define the clinical, pathologic, and genomic factors associated with outcomes to ICI therapy in patients with HCC. Patients with histologically confirmed advanced HCC treated with ICI at Memorial Sloan Kettering Cancer Center from 2012 to 2022 were included. Association between clinical, pathological, and genomic characteristics were assessed with univariable and multivariable Cox regression model for progression-free survival (PFS) and OS. RESULTS: Two-hundred and forty-two patients were treated with ICI-based therapy. Patients were predominantly male (82%) with virally mediated HCC (53%) and Child Pugh A score (70%). Median follow-up was 28 months (0.5-78.4). Median PFS for those treated in 1st line, 2nd line and ≥ 3rd line was 4.9 (range: 2.9-6.2), 3.1 (2.3-4.0), and 2.5 (2.1-4.0) months, respectively. Median OS for those treated in 1st line, 2nd line, and ≥ 3rd line was 16 (11-22), 7.5 (6.4-11), and 6.4 (4.6-26) months, respectively. Poor liver function and performance status associated with worse PFS and OS, while viral hepatitis C was associated with favorable outcome. Genetic alterations were not associated with outcomes. CONCLUSION: Clinicopathologic factors were the major determinates of outcomes for patients with advanced HCC treated with ICI. Molecular profiling did not aid in stratification of ICI outcomes. Future studies should explore alternative biomarkers such as the level of immune activation or the pretreatment composition of the immune tumor microenvironment.

A Novel Approach to Quantify Heterogeneity of Intrahepatic Cholangiocarcinoma: The Hidden-Genome Classifier.

PURPOSE: Intrahepatic cholangiocarcinoma (IHC) is a heterogeneous tumor. The hidden-genome classifier, a supervised machine learning-based algorithm, was used to quantify tumor heterogeneity and improve classification. EXPERIMENTAL DESIGN: A retrospective review of 1,370 patients with IHC, extrahepatic cholangiocarcinoma (EHC), gallbladder cancer (GBC), hepatocellular carcinoma (HCC), or biphenotypic tumors was conducted. A hidden-genome model classified 527 IHC based on genetic similarity to EHC/GBC or HCC. Genetic, histologic, and clinical data were correlated. RESULTS: In this study, 410 IHC (78%) had >50% genetic homology with EHC/GBC; 122 (23%) had >90% homology ("biliary class"), characterized by alterations of KRAS, SMAD4, and CDKN2A loss; 117 IHC (22%) had >50% genetic homology with HCC; and 30 (5.7%) had >90% homology ("HCC class"), characterized by TERT alterations. Patients with biliary- versus non-biliary-class IHC had median overall survival (OS) of 1 year (95% CI, 0.77, 1.5) versus 1.8 years (95% CI, 1.6, 2.0) for unresectable disease and 2.4 years (95% CI, 2.1, NR) versus 5.1 years (95% CI, 4.8, 6.9) for resectable disease. Large-duct IHC (n = 28) was more common in the biliary class (n = 27); the HCC class was composed mostly of small-duct IHC (64%, P = 0.02). The hidden genomic classifier predicted OS independent of FGFR2 and IDH1 alterations. By contrast, the histology subtype did not predict OS. CONCLUSIONS: IHC genetics form a spectrum with worse OS for tumors genetically aligned with EHC/GBC. The classifier proved superior to histologic subtypes for predicting OS independent of FGFR2 and IDH1 alterations. These results may explain the differential treatment responses seen in IHC and may direct therapy by helping stratify patients in future clinical trials.

Cross-fellowship Inter-institutional Exchange: Answering the Call for Hepatopancreatobiliary Training Standardization.

OBJECTIVE: General surgery trainees interested in performing hepatopancreatobiliary (HPB) surgery can choose from multiple fellowship pathways, namely HPB, surgical oncology (SO), and abdominal transplant-HPB (TXP-HPB). Although focused on similar operations, each program offers distinct clinical and technical emphases. DESIGN: An annual inter-institutional exchange between TXP-HPB and SO fellowships, starting in 2014. SETTING AND PARTICIPANTS: TXP-HPB fellows from Washington University in St. Louis (WUSTL) and SO fellows from Memorial Sloan Kettering Cancer Center (MSKCC). RESULTS: About 14 fellows have participated in the exchange so far, 13 of whom responded to our survey. At MSKCC, TXP-HPB fellows performed a median of 24 cases, including 6 major pancreatic resections, 3 major hepatectomies, 4 hepatic artery infusion pump insertions, and 1 major biliary case. At WUSTL, SO fellows performed a median of 16 cases, including 5 liver transplants, 2 major pancreatic resections, 2 major hepatectomies, and 2 major biliary cases. About 92.3% of respondents stated they would repeat the rotation, with SO fellows emphasizing the exposure to vascular anastomoses and transplant-HPB fellows appreciating the oncologic focus. CONCLUSIONS: A monthlong inter-institutional exchange offers a unique opportunity to standardize and improve HPB education.

Salvage Ablative Radiotherapy for Isolated Local Recurrence of Pancreatic Adenocarcinoma following Definitive Surgery.

Introduction: The rate of isolated locoregional recurrence after surgery for pancreatic adenocarcinoma (PDAC) approaches 25%. Ablative radiation therapy (A-RT) has improved outcomes for locally advanced disease in the primary setting. We sought to evaluate the outcomes of salvage A-RT for isolated locoregional recurrence and examine the relationship between subsequent patterns of failure, radiation dose, and treatment volume. Methods: We conducted a retrospective analysis of all consecutive participants who underwent A-RT for an isolated locoregional recurrence of PDAC after prior surgery at our institution between 2016 and 2021. Treatment consisted of ablative dose (BED10 98-100 Gy) to the gross disease with an additional prophylactic low dose (BED10 < 50 Gy), with the elective volume covering a 1.5 cm isotropic expansion around the gross disease and the circumference of the involved vessels. Local and locoregional failure (LF and LRF, respectively) estimated by the cumulative incidence function with competing risks, distant metastasis-free and overall survival (DMFS and OS, respectively) estimated by the Kaplan-Meier method, and toxicities scored by CTCAE v5.0 are reported. Location of recurrence was mapped to the dose region on the initial radiation plan. Results: Among 65 participants (of whom two had two A-RT courses), the median age was 67 (range 37-87) years, 36 (55%) were male, and 53 (82%) had undergone pancreaticoduodenectomy with a median disease-free interval to locoregional recurrence of 16 (range, 6-71) months. Twenty-seven participants (42%) received chemotherapy prior to A-RT. With a median follow-up of 35 months (95%CI, 26-56 months) from diagnosis of recurrence, 24-month OS and DMFS were 57% (95%CI, 46-72%) and 22% (95%CI, 14-37%), respectively, while 24-month cumulative incidence of in-field LF and total LRF were 28% (95%CI, 17-40%) and 36% (95%CI 24-48%), respectively. First failure after A-RT was distant in 35 patients (53.8%), locoregional in 12 patients (18.5%), and synchronous distant and locoregional in 10 patients (15.4%). Most locoregional failures occurred in elective low-dose volumes. Acute and chronic grade 3-4 toxicities were noted in 1 (1.5%) and 5 patients (7.5%), respectively. Conclusions: Salvage A-RT achieves favorable OS and local control outcomes in participants with an isolated locoregional recurrence of PDAC after surgical resection. Consideration should be given to extending high-dose fields to include adjacent segments of at-risk vessels beyond direct contact with the gross disease.