Randomized Prospective Trial of Epidural Analgesia after Open Hepatectomy.

OBJECTIVE: To evaluate whether patient-controlled epidural analgesia (PCEA) improves postoperative pain during ambulation following elective open hepatectomy. BACKGROUND: Strategies to alleviate postoperative pain are a critical element of recovery after surgery. However, the optimal postoperative pain management strategy following open hepatectomy remains unclear. METHODS: We conducted a prospective, nonblinded, randomized comparison of PCEA (intervention) versus intravenous patient-controlled analgesia (IV PCA; control) for postoperative pain following elective open hepatectomy. The primary end point was pain during ambulation on postoperative day (POD) 2. The study was powered to detect a clinically significant 2-point difference on the pain numeric rating scale (NRS). Secondary end points included pain at rest, morbidity, time to return of bowel function, and length of stay. RESULTS: From 2015 to 2020, 231 patients were randomized (116 patients in the PCEA arm and 115 in the IV PCA arm). The incidence of epidural failure was 3% (n=4/116), with no epidural-related complications. Patients in the PCEA arm had a <2-point difference in NRS pain scores during ambulation on POD 2 vs. IV PCA (median 4.0 vs. 5.0, P <0.001). There was no difference in overall complications between the PCEA and IV PCA arms (33% vs. 40%, P =0.276). Secondary outcomes, including pain scores at rest, were similar between the study arms. CONCLUSIONS: PCEA was safe following open hepatectomy and was associated with a small difference in pain with activity on POD 2 that did not reach our pre-specified definition of clinical significance.

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.

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.

SWI/SNF COMPLEX-DEFICIENT UNDIFFERENTIATED CARCINOMA OF THE PANCREAS:CLINICOPATHOLOGIC AND GENOMIC ANALYSIS.

Inactivating alterations in the SWItch/Sucrose Non-Fermentable (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 (IHC) and/or next-generation sequencing (NGS). Cases with alterations in SWI/SNF complex-related proteins/genes were compared to cases without alterations, as well as to 96 conventional pancreatic ductal adenocarcinomas (PDAC). In all tumor groups, MMR 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 < 0.001] 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 IHC were found to have corresponding SMARCB1 deletions by NGS. Analysis of canonical driver mutations for PDAC in these cases showed KRAS (2/5) and TP53 (2/5) abnormalities. Median CPS for PD-L1 (E1L3N) was significantly higher in the undifferentiated carcinomas with/without SWI/SNF deficiency compared to the conventional PDACs (p < 0.001). SWI/SNF-deficient undifferentiated carcinomas were larger (p < 0.001) and occurred in younger patients (p < 0.001). Patients with SWI/SNF-deficient undifferentiated carcinoma had worse overall survival compared to patients with SWI/SNF-retained undifferentiated carcinoma (p = 0.004) and PDAC (p < 0.001). 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.

Treatment Patterns and Outcomes in Pancreatic Cancer: A Comparative Analysis of Ontario and the USA.

BACKGROUND: Comparative studies evaluating quality of care in different healthcare systems can guide reform initiatives. This study seeks to characterize best practices by comparing utilization and outcomes for patients with pancreatic cancer (PC) in the USA and Ontario, Canada. METHODS: Patients (age ≥ 66 years) with PC were identified from the Ontario Cancer Registry and SEER-Medicare databases from 2006 to 2015. Demographics and treatment (surgery, radiation, chemotherapy, or multimodality (surgery and chemotherapy)) were described. In resected patients, neoadjuvant therapy, readmission, and 30- and 90-day postoperative mortality rates were calculated. Survival was assessed using Kaplan-Meier curves. RESULTS: This study includes 38,858 and 11,512 patients with PC from the USA and Ontario, respectively. More female patients were identified in the USA (54.0%) versus Ontario (46.9%). In the entire cohort, US patients received more radiation in addition to other therapies (18.8% vs. 13.5% Ontario) and chemotherapy alone (34.3% vs. 19.0% Ontario). While rates of resection were similar (13.4% USA vs.12.5% Ontario), multimodality therapy was more common in the UAS (9.0% vs. 6.4%). Among resected patients, neoadjuvant chemotherapy was uncommon in both groups, although more frequent in the USA (12.0% vs. 3.2% Ontario). The 30- and 90-day postoperative mortality rates were lower in Ontario vs. the USA (30-day: 3.26% vs. 4.91%; 90-day: 7.08% vs. 10.96%), however, overall survival was similar between the USA and Ontario. CONCLUSIONS: We observed substantive differences in treatment and outcomes between PC patients in the USA and Ontario, which may reflect known differences in healthcare systems. Close evaluation of healthcare policies can inform initiatives to improve care quality.

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.

Gemcitabine with Cisplatin Versus Hepatic Arterial Infusion Pump Chemotherapy for Liver-Confined Unresectable Intrahepatic Cholangiocarcinoma.

BACKGROUND: A post-hoc analysis of ABC trials included 34 patients with liver-confined unresectable intrahepatic cholangiocarcinoma (iCCA) who received systemic chemotherapy with gemcitabine and cisplatin (gem-cis). The median overall survival (OS) was 16.7 months and the 3-year OS was 2.8%. The aim of this study was to compare patients treated with systemic gem-cis versus hepatic arterial infusion pump (HAIP) chemotherapy for liver-confined unresectable iCCA. METHODS: We retrospectively collected consecutive patients with liver-confined unresectable iCCA who received gem-cis in two centers in the Netherlands to compare with consecutive patients who received HAIP chemotherapy with or without systemic chemotherapy in Memorial Sloan Kettering Cancer Center. RESULTS: In total, 268 patients with liver-confined unresectable iCCA were included; 76 received gem-cis and 192 received HAIP chemotherapy. In the gem-cis group 42 patients (55.3%) had multifocal disease compared with 141 patients (73.4%) in the HAIP group (p = 0.023). Median OS for gem-cis was 11.8 months versus 27.7 months for HAIP chemotherapy (p < 0.001). OS at 3 years was 3.5% (95% confidence interval [CI] 0.0-13.6%) in the gem-cis group versus 34.3% (95% CI 28.1-41.8%) in the HAIP chemotherapy group. After adjusting for male gender, performance status, baseline hepatobiliary disease, and multifocal disease, the hazard ratio (HR) for HAIP chemotherapy was 0.27 (95% CI 0.19-0.39). CONCLUSIONS: This study confirmed the results from the ABC trials that survival beyond 3 years is rare for patients with liver-confined unresectable iCCA treated with palliative gem-cis alone. With HAIP chemotherapy, one in three patients was alive at 3 years.

Higher Postoperative Mortality and Inferior Survival After Right-Sided Liver Resection for Perihilar Cholangiocarcinoma: Left-Sided Resection is Preferred When Possible.

BACKGROUND: A right- or left-sided liver resection can be considered in about half of patients with perihilar cholangiocarcinoma (pCCA), depending on tumor location and vascular involvement. This study compared postoperative mortality and long-term survival of right- versus left-sided liver resections for pCCA. METHODS: Patients who underwent major liver resection for pCCA at 25 Western centers were stratified according to the type of hepatectomy-left, extended left, right, and extended right. The primary outcomes were 90-day mortality and overall survival (OS). RESULTS: Between 2000 and 2022, 1701 patients underwent major liver resection for pCCA. The 90-day mortality was 9% after left-sided and 18% after right-sided liver resection (p < 0.001). The 90-day mortality rates were 8% (44/540) after left, 11% (29/276) after extended left, 17% (51/309) after right, and 19% (108/576) after extended right hepatectomy (p < 0.001). Median OS was 30 months (95% confidence interval [CI] 27-34) after left and 23 months (95% CI 20-25) after right liver resection (p < 0.001), and 33 months (95% CI 28-38), 27 months (95% CI 23-32), 25 months (95% CI 21-30), and 21 months (95% CI 18-24) after left, extended left, right, and extended right hepatectomy, respectively (p < 0.001). A left-sided resection was an independent favorable prognostic factor for both 90-day mortality and OS compared with right-sided resection, with similar results after excluding 90-day fatalities. CONCLUSIONS: A left or extended left hepatectomy is associated with a lower 90-day mortality and superior OS compared with an (extended) right hepatectomy for pCCA. When both a left and right liver resection are feasible, a left-sided liver resection is preferred.

Outcome of patients with perihilar cholangiocarcinoma and previous biliary instrumentation: an observational study.

BACKGROUND: To assess the outcome of previously untreated patients with perihilar cholangiocarcinoma who present to a cancer referral center with or without pre-existing trans-papillary biliary drainage. METHODS: Consecutive patients with a diagnosis of perihilar cholangiocarcinoma presenting between January 1, 2013, and December 31, 2017, were identified from a prospective surgical database and by a query of the institutional database. Of 237 patients identified, 106 met inclusion criteria and were reviewed. Clinical information was obtained from the Electronic Medical Record and imaging studies were reviewed in the Picture Archiving and Communication System. RESULTS: 73 of 106 patients (69%) presenting with a new diagnosis of perihilar cholangiocarcinoma underwent trans-papillary biliary drainage (65 endoscopic and 8 percutaneous) prior to presentation at our institution. 8 of the 73 patients with trans-papillary biliary drainage (11%) presented with and 5 developed cholangitis; all 13 (18%) required subsequent intervention; none of the patients without trans-papillary biliary drainage presented with or required drainage for cholangitis (p = 0.008). Requiring drainage for cholangitis was more likely to delay treatment (p = 0.012) and portended a poorer median overall survival (13.6 months, 95%CI [4.08, not reached)] vs. 20.6 months, 95%CI [18.34, 37.51] p = 0.043). CONCLUSION: Trans-papillary biliary drainage for perihilar cholangiocarcinoma carries a risk of cholangitis and should be avoided when possible. Clinical and imaging findings of perihilar cholangiocarcinoma should prompt evaluation at a cancer referral center before any intervention. This would mitigate development of cholangitis necessitating additional drainage procedures, delaying treatment and potentially compromising survival.

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.

The Image-to-Physical Liver Registration Sparse Data Challenge: comparison of state-of-the-art using a common dataset.

Purpose: Computational methods for image-to-physical registration during surgical guidance frequently rely on sparse point clouds obtained over a limited region of the organ surface. However, soft tissue deformations complicate the ability to accurately infer anatomical alignments from sparse descriptors of the organ surface. The Image-to-Physical Liver Registration Sparse Data Challenge introduced at SPIE Medical Imaging 2019 seeks to characterize the performance of sparse data registration methods on a common dataset to benchmark and identify effective tactics and limitations that will continue to inform the evolution of image-to-physical registration algorithms. Approach: Three rigid and five deformable registration methods were contributed to the challenge. The deformable approaches consisted of two deep learning and three biomechanical boundary condition reconstruction methods. These algorithms were compared on a common dataset of 112 registration scenarios derived from a tissue-mimicking phantom with 159 subsurface validation targets. Target registration errors (TRE) were evaluated under varying conditions of data extent, target location, and measurement noise. Jacobian determinants and strain magnitudes were compared to assess displacement field consistency. Results: Rigid registration algorithms produced significant differences in TRE ranging from 3.8±2.4 mm to 7.7±4.5 mm, depending on the choice of technique. Two biomechanical methods yielded TRE of 3.1±1.8 mm and 3.3±1.9 mm, which outperformed optimal rigid registration of targets. These methods demonstrated good performance under varying degrees of surface data coverage and across all anatomical segments of the liver. Deep learning methods exhibited TRE ranging from 4.3±3.3 mm to 7.6±5.3 mm but are likely to improve with continued development. TRE was weakly correlated among methods, with greatest agreement and field consistency observed among the biomechanical approaches. Conclusions: The choice of registration algorithm significantly impacts registration accuracy and variability of deformation fields. Among current sparse data driven image-to-physical registration algorithms, biomechanical simulations that incorporate task-specific insight into boundary conditions seem to offer best performance.

Simulation of Image-Guided Microwave Ablation Therapy Using a Digital Twin Computational Model.

Emerging computational tools such as healthcare digital twin modeling are enabling the creation of patient-specific surgical planning, including microwave ablation to treat primary and secondary liver cancers. Healthcare digital twins (DTs) are anatomically one-to-one biophysical models constructed from structural, functional, and biomarker-based imaging data to simulate patient-specific therapies and guide clinical decision-making. In microwave ablation (MWA), tissue-specific factors including tissue perfusion, hepatic steatosis, and fibrosis affect therapeutic extent, but current thermal dosing guidelines do not account for these parameters. This study establishes an MR imaging framework to construct three-dimensional biophysical digital twins to predict ablation delivery in livers with 5 levels of fat content in the presence of a tumor. Four microwave antenna placement strategies were considered, and simulated microwave ablations were then performed using 915 MHz and 2450 MHz antennae in Tumor Naïve DTs (control), and Tumor Informed DTs at five grades of steatosis. Across the range of fatty liver steatosis grades, fat content was found to significantly increase ablation volumes by approximately 29-l42% in the Tumor Naïve and 55-60% in the Tumor Informed DTs in 915 MHz and 2450 MHz antenna simulations. The presence of tumor did not significantly affect ablation volumes within the same steatosis grade in 915 MHz simulations, but did significantly increase ablation volumes within mild-, moderate-, and high-fat steatosis grades in 2450 MHz simulations. An analysis of signed distance to agreement for placement strategies suggests that accounting for patient-specific tumor tissue properties significantly impacts ablation forecasting for the preoperative evaluation of ablation zone coverage.

Comparison study of intraoperative surface acquisition methods on registration accuracy for soft-tissue surgical navigation.

Purpose: To study the difference between rigid registration and nonrigid registration using two forms of digitization (contact and noncontact) in human in vivo liver surgery. Approach: A Conoprobe device attachment and sterilization process was developed to enable prospective noncontact intraoperative acquisition of organ surface data in the operating room (OR). The noncontact Conoprobe digitization method was compared against stylus-based acquisition in the context of image-to-physical registration for image-guided surgical navigation. Data from n=10 patients undergoing liver resection were analyzed under an Institutional Review Board-approved study at Memorial Sloan Kettering Cancer Center. Organ surface coverage of each surface acquisition method was compared. Registration accuracies resulting from the acquisition techniques were compared for (1) rigid registration method (RRM), (2) model-based nonrigid registration method (NRM) using surface data only, and (3) NRM with one subsurface feature (vena cava) from tracked intraoperative ultrasound (NRM-VC). Novel vessel centerline and tumor targets were segmented and compared to their registered preoperative counterparts for accuracy validation. Results: Surface data coverage collected by stylus and Conoprobe were 24.6%±6.4% and 19.6%±5.0%, respectively. The average difference between stylus data and Conoprobe data using NRM was -1.05 mm and using NRM-VC was -1.42 mm, indicating the registrations to Conoprobe data performed worse than to stylus data with both NRM approaches. However, using the stylus and Conoprobe acquisition methods led to significant improvement of NRM-VC over RRM by average differences of 4.48 and 3.66 mm, respectively. Conclusion: The first use of a sterile-field amenable Conoprobe surface acquisition strategy in the OR is reported for open liver surgery. Under clinical conditions, the nonrigid registration significantly outperformed standard-of-care rigid registration, and acquisition by contact-based stylus and noncontact-based Conoprobe produced similar registration results. The accuracy benefits of noncontact surface acquisition with a Conoprobe are likely obscured by inferior data coverage and intrinsic noise within acquisition systems.

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.

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.

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.

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.

Concordance in Oncogenic Alterations Between the Primary Tumor and Advanced Disease: Insights Into the Heterogeneity of Intrahepatic Cholangiocarcinoma.

PURPOSE: Intrahepatic cholangiocarcinoma (ICCA) is characterized by significant phenotypic and clinical heterogeneities and poor response to systemic therapy, potentially related to underlying heterogeneity in oncogenic alterations. We aimed to characterize the genomic heterogeneity between primary tumors and advanced disease in patients with ICCA. METHODS: Biopsy-proven CCA specimens (primary tumor and paired advanced disease [metastatic disease, progressive disease on systemic therapy, or postoperative recurrence]) from two institutions were subjected to targeted next-generation sequencing. Overall concordance (oncogenic driver mutations, copy number alterations, and fusion events) and mutational concordance (only oncogenic mutations) were compared across paired samples. A subgroup analysis was performed on the basis of exposure to systemic therapy. Patients with extrahepatic CCA (ECCA) were included as a comparison group. RESULTS: Sample pairs from 65 patients with ICCA (n = 54) and ECCA (n = 11) were analyzed. The median time between sample collection was 19.6 months (range, 2.7-122.9). For the entire cohort, the overall oncogenic concordance was 49% and the mutational concordance was 62% between primary and advanced disease samples. Subgroup analyses of ICCA and ECCA revealed overall/mutational concordance rates of 47%/58% and 60%/84%, respectively. Oncogenic concordance was similarly low for pairs exposed to systemic therapy between sample collections (n = 50, 53% overall, 68% mutational). In patients treated with targeted therapy for IDH1/2 alterations (n = 6) or FGFR2 fusions (n = 3), there was 100% concordance between the primary and advanced disease specimens. In two patients, FGFR2 (n = 1) and IDH1 (n = 1) alterations were detected de novo in the advanced disease specimens. CONCLUSION: The results reflect a high degree of heterogeneity in ICCA and argue for reassessment of the dominant driver mutations with change in disease status.

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.