Hallemeier, Christopher Leigh

Abstract Background Optimal treatment following first-line immunotherapy for advanced hepatocellular carcinoma (HCC) remains uncertain. This study evaluated futibatinib, a pan-FGFR inhibitor, combined with pembrolizumab in previously treated patients with FGF19-expressing HCC. Methods Eligible patients were ≥18 years old with advanced HCC, prior systemic therapy, Child-Pugh A-B7 liver function, ECOG 0–2, and FGF19 overexpression. Patients received futibatinib 20 mg orally daily plus pembrolizumab 200 mg intravenously every 3 weeks. The primary endpoint was progression-free survival at 6 months (PFS6). Secondary endpoints included overall survival (OS), objective response rate (ORR), quality of life, and safety. Results Between August 2021 and March 2024, 14 patients enrolled and 13 were evaluable. Median age was 72 years (range, 60–87), 53.8% were male, 92.3% had Child-Pugh A liver function, and all had received prior immunotherapy. Median progression-free survival was 15 weeks (95% CI, 9.0–NE), with a PFS6 rate of 23.1% (95% CI, 8.6–62.3%). ORR was 0% (95% CI, 0–24.7%), while stable disease was observed in 53.9% of patients. Median OS was 55.7 weeks (95% CI, 47.3–NE). Grade ≥3 adverse events occurred in 69.2% of patients, and grade ≥4 adverse events in 15.4%. One grade 5 event (acute-on-chronic kidney injury) was deemed unrelated to treatment. Common adverse events included hyperphosphatemia, fatigue, diarrhea, elevated transaminases, dry eye, nail changes, rash, and oral mucositis. Conclusions Futibatinib plus pembrolizumab demonstrated an acceptable safety profile but did not meet efficacy thresholds supporting further study in FGF19-expressing HCC. Effective post-immunotherapy treatment strategies remain an unmet need.

Objectives: Rates of locoregional recurrence and distant metastases are high following curative-intent resection for patients with localized pancreatic adenocarcinoma. Adjuvant therapies have been investigated with the intent to reduce the risk of recurrence and improve OS. The objective of this study is to update and summarize the current evidence for adjuvant therapy following surgical resection for nonmetastatic PDAC with a focus on high-level evidence and randomized controlled trials is provided. Methods: This multispecialty-led committee included gastrointestinal radiation and medical oncology, gastroenterology, radiology, and surgical oncology. Using the population, intervention, comparator, outcome, timing and study design framework, evidence regarding treatment outcomes was assessed using Cochrane and PRISMA methodology. Eligible studies included prospective and retrospective (n≥25) studies published between January 1, 2013 and February 13, 2026, from Ovid MEDLINE, Ovid EMBASE, Ovid Cochrane Database of Systematic Review, and Scopus databases. Study type and quality were assessed. Well-established RAND/UCLA consensus methodology (modified Delphi) was used to rate the appropriateness of the treatment options. Results: Of the 74 references used as evidence, 74 are categorized as therapeutic references. Study type and quality for the references were assessed, and included 31 well-designed studies (phase II randomized and phase III), 14 moderately well-designed studies that account for most common biases (matched cohort and phase II studies), 28 studies with design limitations (retrospective reviews), and 1 reference meta-analysis. Conclusions: This systematic review and guidelines provide up-to-date recommendations focusing on recent advancements for adjuvant treatment of resected PDAC using modern systemic therapy regimens and selective use of radiotherapy using modern techniques.

Abstract This literature‐based systematic review and associated guidelines provide evidence‐based paradigms for the management of locoregionally recurrent rectal cancer (LRRC). This multispecialty committee included gastrointestinal radiation and medical oncology, gastroenterology, radiology, and colorectal surgery. As is the standard, the previously described American Radium Society Appropriate Use Criteria methodology for this project was followed rigorously, with the Population, Intervention, Comparator, Outcome, Timing, and Study Design framework and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses methodology to assess the evidence. RAND/University of California Los Angeles consensus methodology (modified Delphi) was used to rate the appropriateness of treatment options. Published between January 1, 2013, and July 16, 2025, 116 peer‐reviewed trials provided the evidence: 10 were well‐designed randomized phase 2/3 trials, 29 were moderately well designed trials that accounted for most common biases (matched cohort and phase 2), 76 trials had design limitations (retrospective), and one was a meta‐analysis. Clinical cases were created as examples to illustrate current acceptable management of LRRC. Treatment and prognosis are influenced by prior therapy and the site(s) and extent of LRRC. The ability to achieve a margin‐negative surgical resection is the ultimate determinant of survival and local control. Preoperative systemic therapy, radiation therapy, or a combination of the two can facilitate tumor downsizing and improve the likelihood of a margin‐negative resection. An individualized multidisciplinary approach is required to ensure the best outcome. Although this review does not suggest a major alteration of current practice, it provides reassuring evidence of the importance of combined‐modality therapy.

PURPOSE External beam radiation therapy (EBRT) has gained delayed acceptance as a recommended first-line treatment modality for patients with hepatocellular carcinoma (HCC), given limited evidence that it improves overall survival (OS). We analyzed individual patient data (IPD) from an international cohort to assess OS among patients with HCC treated with EBRT. METHODS We performed a systematic review of publications that assessed EBRT, met prespecified technical standards for HCC, and reported OS (search date December 15, 2022). Corresponding authors were invited to submit IPD for the study. We performed Kaplan-Meier survival analyses to determine OS and restricted mean survival time (RMST) stratified by Barcelona Clinic Liver Cancer (BCLC) stage and treatment status (ie, treatment-naïve and experienced). We performed random effects Cox proportional hazards modeling to assess clinical characteristics associated with OS. RESULTS Data were provided on 4,913 patients treated with EBRT with a median follow-up time of 5.0 years. The median OS was 6.8 years (95% CI, 5.7 to 8.7) for BCLC-0 and 4.6 years (95% CI, 4.1 to 5.1) for BCLC-A. Among treatment-naïve patients, the median OS was not reached (95% CI, 8.6 to not reached) for BCLC-0 and was 5.4 years (95% CI, 4.5 to 6.7) for BCLC-A. In multivariable models, more advanced BCLC stage, higher tumor burden, worse performance status, and Child-Pugh class B or C were associated with a higher risk of mortality. Ablative radiation dose and more recent year of treatment were associated with a reduced risk of death. CONCLUSION To our knowledge, this study represents the largest multinational cohort of patients with HCC treated with EBRT. OS outcomes with EBRT for very early- and early-stage HCC appear to be comparable with resection, thermal ablation, and other ablative locoregional therapies. These data support the inclusion of EBRT in the BCLC HCC clinical decision-making process.

Abstract Background: Hepatocellular carcinoma (HCC) is largely refractory to immune checkpoint blockade due to immune exclusion, stromal barriers, and aberrant vasculature. We evaluated whether multimodal therapy - external beam radiotherapy (EBRT) for antigen release, intratumoral dendritic cell (DC) vaccination for antigen presentation, PD-L1 blockade for immune activation, and VEGF inhibition for vascular normalization - could convert “cold” HCC tumors into sustained immune-inflamed states. Methods: Serial biopsies (baseline, post-EBRT, end-of-treatment [EOT], and progression [PD] when available) from three patients enrolled in an ongoing phase II trial (NCT03942328) underwent multiplex immunofluorescence, spatial neighborhood analysis, and transcriptomic profiling. Longitudinal changes in cellular composition, immune-stromal architecture, spatial contact networks, and pathway activity were compared. Results: Baseline tumor microenvironments (TMEs) were strongly immune-excluded, dominated by tumor (PanCK+60-70%) and stroma (SMA+/Vimentin+25-30%) with sparse immune infiltration (<10-15%). Post-therapy, immune complexity and spatial connectivity increased 2-3-fold in all patients. Patient 1 showed robust cold-to-hot conversion with CD8+(3x), CD4+(2.2x), and DC (2.3x) expansion, increased CD8-DC interactions (2.5x), and reduced tumor fraction (-40%). Transcriptomics showed marked upregulation of IFN-γ (↑3.4x), HLA-DRA (↑2.7x), and reductions in VEGFR2 (↓50%) and HIF1A (↓40%), consistent with vascular normalization. Patient 2 exhibited stromal/vascular remodeling and improved T-cell infiltration but restricted immune diversity, with CD4+/CD8+ dyads (↑2.2x) and B/NK cells(↓ 60%). Neighborhood diversity rose (3→7 communities) and immune-tumor proximity improved (distance ↓ 35%). Patient 3 showed transient inflaming with CD8+(↑3x), DC(↑2x), and new CD4-CD20/CD4-CD56 interactions, followed by relapse marked by stromal/myeloid re-expansion (SMA+↑1.8x, CD14+↑2.5x), angiogenic resurgence (VEGFR2/CD34+↑2.2x), contraction of immune networks, and genomic shift from activating CTNNB1 mutation loss to ATM gain. DCs accumulated but localized mainly to DC-DC or DC-myeloid niches, indicating non-productive antigen presentation. Conclusions: Multimodal EBRT+DC+PD-L1/VEGF blockade induces four-sided synergistic TME reprogramming - antigen release, immune priming, checkpoint release, and vascular normalization - promoting cold-to-hot conversion in HCC. Durable inflaming correlates with sustained T-cell/DC expansion and vascular remodeling, whereas relapse reflects stromal/myeloid reinforcement and genomic adaptation. These findings define mechanistic trajectories of TME remodeling and highlight actionable barriers to sustained immunotherapy response in HCC. Citation Format: Lionel Aurelien Kankeu Fonkoua, Christopher L. Hallemeier, Basim Salem, Arina Tkachuk, Kaitlynn McCay, Panwen Wang, Ying Li, Thomas D. Atwell, Krishan R. Jethwa, Caitlin Conboy, Nguyen H. Tran, Leslie A. Washburn, Melody Wu, Chen Wu, Andre De Menezes Silva Corraes, Rondell P. Graham, Jose Caetano Villasboas, Kevin Regan, Zuoyi Shao, Rayaan Kamal, Nathan R. Foster, Haidong Dong, Sean Park, Yi Lin, Lewis R. Roberts. Multimodal immunotherapy remodels the tumor microenvironment in hepatocellular carcinoma: Integrative spatial and transcriptomic profiling from a Phase II trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7935.

Abstract Introduction: Liver cancer remains a leading cause of cancer mortality globally with limited treatment options for patients (pts) with unresectable hepatocellular carcinoma [HCC] and intrahepatic cholangiocarcinoma [iCCA][1,2,3,4]. We hypothesize that combining the intratumoral dendritic cell (DC) vaccination after external beam radiotherapy (EBRT) without (phase I) and with (phase II) systemic atezolizumab and bevacizumab (atezo/bev for HCC) would enhance tumor-specific immunity and improve clinical outcomes, and present preliminary results from our phase I/II trial (NCT03942328). Methods: Peripheral blood mononuclear cells (PBMCs) were collected at baseline (PRE), after radiation (EBRT), and after completion of DC without or with atezo/bev (POST). Single-cell RNA sequencing with TCR sequencing were analyzed using CellRanger v7.0.1, Immunopipe, Seurat v5.3.0, & Gene-set enrichment analysis (GSEA). Long EFS (EFS-L) is defined as >=12 months (mo) for phase I and >=18mo for phase II, and short EFS (EFS-S) below that. Results: Seventeen patients have been analyzed to date (Phase I: n=8 [4 HCC, 4 iCCA]; Phase II: n=9 HCC). 674,106 cells were sequenced (146,843 PRE; 168,838 EBRT; 114,437 POST). GSEA for EFS-L vs EFS-S were comparable at PRE, EBRT and POST between phase I and phase II. EFS-S was associated with enrichment of interferon alpha (IFNα; B naïve, monocytes, pDC, cDC2, NK, Treg, CD8 Tcm and Tem at PRE and POST; B intermediate, CD4 Tem and NK at EBRT) and reactive oxygen species (ROS; PRE: pDC, CD8 Tcm, Tem. EBRT: CD4 Tem. POST: CD8 T naïve Tem, CD4 Tcm & Tem, cDC2) pathways. In contrast, EFS-L was associated with enrichment of WNT-β-catenin (WNT; CD14 mono at EBRT & POST, B intermediate at EBRT), TGFb (PRE: NK; EBRT: B intermed, CD4 Tem; POST: monocytes, CD4 naïve & Tem, pDC, cDC2), and angiogenesis (EBRT: NK; POST: monocytes, cDC2) pathways. Interestingly, enrichment of protein secretion pathway in NK cells was associated with EFS-L, but among other cells were associated with EFS-S (PRE: CD16 mono, Treg; POST: CD16 mono, CD4 & D8 Tem). Compared to phase I, addition of atezo/bev in phase II pts was associated with a significant increase in Gini coefficient (p<0.0001), suggesting expansion of certain TCR clones, along with a trend for increased Gini coefficient from Pre to Post in both phase I and II. Conclusions: Preliminary analysis of this study combining EBRT with intratumoral DC vaccination +/- PD-L1/VEGF blockade identified distinct treatment-related changes in systemic cellular immune profiles. Enhanced TCR clonal diversity in phase II suggests added immunologic benefit from PD-L1/VEGF blockade. As accrual continues, integrated analyses will identify systemic immune correlates of clinical benefit and resistance to this multimodal immunotherapy approach. Citation Format: Melody Wu, Panwen Wang, Chen Wu, Ying Li, Christopher L. Hallemeier, Thomas D. Atwell, Nguyen H. Tran, Andre de Menezes Silva Corraes, Kevin Regan, Zuoyi Shao, Rayaan Kamal, Haidong Dong, Lewis R. Roberts, Sean Park, Yi Lin, Lionel Aurelien Kankeu Fonkoua. Radiation-dendritic cell combination therapy drives systemic cellular immune shifts in liver cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3741.

Objectives: To summarize recent high-quality trials and provide an update to the original 2022 American College of Radiology Appropriate Use Criteria for Treatment of Locoregional Gastric Adenocarcinoma. This multi-specialty-led committee included gastrointestinal radiation and medical oncology, gastroenterology, radiology, and surgical oncology. Methods: Using the population, intervention, comparator, outcome, timing, and study design framework, the evidence was assessed using Cochrane and PRISMA 2020 methodology. Eligible studies included prospective Phase II/II trials and select retrospective studies published between 5/1/2020 and 8/1/2025 in the Embase, Medline, and Pubmed databases. Study type and quality were assessed. Well-established RAND-UCLA consensus methodology (modified Delphi) was used to rate the appropriateness of the treatment options. Results: ARS AUC recommendations include adjuvant FLOT chemotherapy for localized gastric adenocarcinoma after neoadjuvant FLOT and surgery, poCT or perioperative chemoimmunotherapy for localized gastric adenocarcinoma, adjuvant chemotherapy +/− CRT for localized gastric adenocarcinoma that undergoes upfront surgery, and systemic therapy alone for localized gastric adenocarcinoma in a medically inoperable patient. Conclusions: This updated ARS AUC summary provides guidelines for the multimodality treatment of resectable gastric adenocarcinoma.

Background/Objectives: We performed a systematic review of preclinical literature on the use of high-LET particle therapy, DDRi, and/or immunotherapy specifically in pMMR colorectal cancer. Methods: A systematic review of the literature published between 2014 and 2025 was conducted across major databases. Studies were included if they examined particle radiotherapy (e.g., proton, alpha, and carbon) or X-ray radiation either alone or in combination with DDRi and/or immune checkpoint inhibitors (ICIs) in pMMR colorectal cancer models. Results: In total, 131 studies met the inclusion criteria, including 70 preclinical studies. These studies consistently demonstrate that high-LET radiation amplifies immunogenic cell death, increases cGAS-STING pathway activation, and enhances tumor antigen presentation, thereby fostering greater immune infiltration and systemic antitumor responses. Concurrent irradiation with DDRi enhances persistent DNA damage and cytosolic DNA accumulation. In murine models, high-LET therapies show excellent local control, with manageable toxicity profiles. Combination regimens with ICIs exhibit improved local control and elicit systemic antitumor immune responses. Conclusions: High-LET particle radiation and/or the use of concurrent DDRi with ICI have significant preclinical evidence of immunostimulatory effects in pMMR rectal adenocarcinoma and increased response rates to immunotherapy. The clinical evidence will be reviewed in the companion manuscript.

Background/Objectives: We performed a systematic review of the current clinical and preclinical literature on the use of particle therapy, DDRi, and/or immunotherapy, specifically for pMMR colorectal cancer. Methods: A systematic review of the literature published between 2014 and 2025 was conducted across major databases. Studies were included if they examined particle radiotherapy (e.g., proton, alpha, carbon) either alone or in combination with DDRi and/or immune checkpoint inhibitors (ICI), or X-ray radiotherapy (XRT) in combination with DDRi/ICI. Results: In total, 133 studies met the inclusion criteria, including 62 clinical studies. Clinically, particle therapies show excellent local control and normal tissue sparing, with manageable toxicity profiles. Trials with any form of radiation and DDRi are few, potentially owing to toxicity concerns. ICI combinations showed promising efficacy with XRT, with no randomized trials comparing them to particle radiation. Conclusions: Particle radiation and/or DDRi have significant preclinical evidence of immunostimulatory effects in pMMR rectal adenocarcinoma and increase response rates to immunotherapy (presented in the companion manuscript). Despite strong preclinical evidence and rationale, clinical trials including all three modalities are scarce. Existing evidence suggests a potential benefit based on extrapolation from photon-based studies and supports prospective evaluation with careful attention to treatment-related toxicity, which remains a concern.

334 Background: Sarcopenia, or decreased skeletal muscle mass, has been associated with worse surgical and oncologic outcomes across multiple malignancies. This study investigates the impact of sarcopenia on outcomes after multimodal therapy for esophageal cancer. Methods: Retrospective observational cohort study including adult patients who underwent neoadjuvant therapy followed by esophagectomy for primary esophageal cancer from January 2000 - December 2021. A fully automated abdominal segmentation using deep convolutional neural network was utilized to calculate skeletal muscle index (SMI) from preoperative CT scans performed at our institution. Males with SMI <52.4 cm 2 /m 2 and females with SMI <38.5 cm 2 /m 2 at any point before surgery were classified as sarcopenic. The relationship between sarcopenia and patient demographics, operative details, and complications were explored using chi-square tests. The relationship between sarcopenia and disease-free survival and overall survival were investigated using parsimonious multivariable analysis retaining variables with p-value <0.05 using backward selection method. Results: We identified 200 patients meeting the study criteria with 142 (71%) having sarcopenia at any time prior to surgery. Patients with sarcopenia were significantly older [65.2 (59.6, 71.2) vs 63 (53.6, 67.5), p = .023] and more likely to have had open surgery [129 (90.8%) vs 46 (79.3%), p = .034]. There were no significant differences in sex, history of diabetes, coronary artery disease, renal disease, smoking, cancer type, cancer stage, tumor size, tumor location, or margin status between sarcopenic groups ( p > .05). Sarcopenic patients were significantly more likely to require blood transfusion ≥3 units after esophagectomy [79 (55.6%) vs 8 (13.8%), p < .001] or to experience complications requiring surgical intervention [36 (24.6%) vs 7 (12.1%), p = .048]. Multivariate analysis revealed that sarcopenia was associated with disease-free and overall survival (Table). Conclusions: Sarcopenia is a prognostic factor in patients undergoing multimodal therapy for esophageal cancer. Interventions that aim to prevent decreases in SMI after initiating neoadjuvant therapy should be investigated. Multivariate analysis with sarcopenia predicting outcomes. Disease free survivalHR (95% CI) p-value Overall survivalHR (95% CI) p-value Age 1.04 (1.02, 1.06) < .001 1.04 (1.02, 1.07) < .001 Epicenter Middle Upper 1.88 (1.21, 2.86)3.16 (1.67, 5.98) .001.005< .001 1.96 (1.26, 3.04)4.00 (1.90, 8.44) < .001.003< .001 Stage Stage II Stage III Stage IV 1.88 (0.95, 3.71)2.90 (1.46, 5.75)16.02 (6.12, 41.93) < .001.069.002< .001 1.65 (0.83, 3.25)2.76 (1.37, 5.55)10.14 (4.03, 25.53) < .001.151.005< .001 Cancer type - - 1.76 (1.03, 3.02) .039 Transfusion > 3 pRBC - - 1.54 (0.99, 2.40) .057 BMI prior to cancer diagnosis - - 0.98 (0.94, 1.01 .208 Sarcopenic 1.76 (1.16, 2.67) .007 1.64 (1.04, 2.60) .033