Advances in the management of pancreatic ductal adenocarcinoma

Association of personalized and tumor-informed ctDNA with patient survival outcomes in pancreatic adenocarcinoma

INTRODUCTION

Personalized and tumor-informed circulating tumor DNA (ctDNA) testing is feasible and allows for molecular residual disease (MRD) identification in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

In this retrospective analysis of commercial cases from multiple US institutions, personalized, tumor-informed, whole-exome sequenced, and germline-controlled ctDNA levels were quantified and analyzed in patients with PDAC. Plasma samples (n = 1329) from 298 clinically validated patients were collected at diagnosis, perioperatively (MRD-window; within 2-12 weeks after surgery, before therapy), and during surveillance (>12 weeks post-surgery if no ACT or starting 4 weeks post-ACT) from November 2019 to March 2023.

RESULTS

Of the initially diagnosed patients with stages I-III PDAC who went for resection, the median follow-up time from surgery was 13 months (range 0.1-214). Positive ctDNA detection rates were 29% (29/100) and 29.6% (45/152) during the MRD and surveillance windows, respectively. Positive ctDNA detection was significantly associated with shorter DFS within the MRD window (median DFS of 6.37 months for ctDNA-positive vs 33.31 months for ctDNA-negative patients; HR: 5.45, P < .0001) as well as during the surveillance period (median DFS: 11.40 months for ctDNA-positive vs NR for ctDNA-negative; HR: 12.38, P < .0001). Additionally, DFS was significantly better with KRAS wildtype status followed by KRASG12R (HR: 0.99, P = .97), KRASG12D (HR: 1.42, P = .194), and worse with KRASG12V (HR: 2.19, P = .002) status. In multivariate analysis, ctDNA detection at surveillance was found to be the most significant prognostic factor for recurrence (HR: 24.28, P < .001).

CONCLUSIONS

Perioperative tumor-informed ctDNA detection in PDAC is feasible across all stages and is associated with patient survival outcomes.

Impact of N-Terminal PEGylation on Synthesis and Purification of Peptide-Based Cancer Epitopes for Pancreatic Ductal Adenocarcinoma (PDAC)

Peptide-based cancer vaccines have shown promising results in preclinical trials focusing on tumor immunotherapy. However, the presence of hydrophobic amino acid segments within these peptide sequences poses challenges in their synthesis, purification, and solubility, thereby hindering their potential use as cancer vaccines. In this study, we successfully synthesized peptide sequences derived from mesothelin (MSLN), a tumor-associated antigen overexpressed in pancreatic ductal adenocarcinoma (PDAC) by conjugating them with monodisperse polyethylene glycol (PEG). By PEGylating mesothelin epitopes of varying lengths (ranging from 9 to 38 amino acids) and hydrophobicity (60-90%), we achieved an effective method to improve the peptide yield and facilitate the processes of synthesis and purification. PEGylation significantly enhanced the solubility, facilitating the single-step purification of lengthy hydrophobic peptides. Most importantly, PEGylation did not compromise cell viability and had little to no effect on the immunogenicity of the peptides. In contrast, the addition of a palmitoyl group to increase immunogenicity led to reduced yield and solubility. Overall, PEGylation proves to be an effective technique for enhancing the solubility and broadening the range of utility of diverse long hydrophobic peptides.

Evaluation of the cytotoxic and immunomodulatory effects of sonodynamic therapy in human pancreatic cancer spheroids

Sonodynamic therapy (SDT) exploits the energy generated by ultrasound (US) to activate sound-sensitive drugs (sonosensitizers), leading to the generation of reactive oxygen species (ROS) and cancer cell death. Two-dimensional (2D) and three-dimensional (3D) cultures of human pancreatic cancer BxPC-3 cells were chosen as the models with which to investigate the therapeutic effects of the US-activated sonosensitizer IR-780 as pancreatic cancer is still one of the most lethal types of cancer. The effects of SDT, including ROS production, cancer cell death and immunogenic cell death (ICD), were extensively investigated. When subjected to US, IR-780 triggered significant ROS production and caused cancer cell death after 24 h (p ≤ 0.01). Additionally, the activation of dendritic cells (DCs) led to an effective immune response against the cancer cells undergoing SDT-induced death. BxPC-3 spheroids were developed and studied extensively to validate the findings observed in 2D BxPC-3 cell cultures. An analysis of the pancreatic cancer spheroid section revealed significant SDT-induced cancer cell death after 48 h after the treatment (p ≤ 0.01), with this being accompanied by the presence of SDT-induced damage-associated molecular patterns (DAMPs), such as calreticulin (CRT) and high mobility group box 1 (HMGB1). In conclusion, the data obtained demonstrates the anticancer efficacy of SDT and its immunomodulatory potential via action as an ICD-inducer.

Ultra-sensitive CTC-based liquid biopsy for pancreatic cancer enabled by large blood volume analysis

The limited sensitivity of circulating tumor cell (CTC) detection in pancreatic adenocarcinoma (PDAC) stems from their extremely low concentration in the whole circulating blood, necessitating enhanced detection methodologies. This study sought to amplify assay-sensitivity by employing diagnostic leukapheresis (DLA) to screen large blood volumes. Sixty patients were subjected to DLA, with a median processed blood volume of ~ 2.8 L and approximately 5% of the resulting DLA-product analyzed using CellSearch (CS). Notably, DLA significantly increased CS-CTC detection to 44% in M0-patients and 74% in M1-patients, yielding a 60-fold increase in CS-CTC enumeration. DLA also provided sufficient CS-CTCs for genomic profiling, thereby delivering additional genomic information compared to tissue biopsy samples. DLA CS-CTCs exhibited a pronounced negative prognostic impact on overall survival (OS), evidenced by a reduction in OS from 28.6 to 8.5 months (univariate: p = 0.002; multivariable: p = 0.043). Additionally, a marked enhancement in sensitivity was achieved (by around 3-4-times) compared to peripheral blood (PB) samples, with positive predictive values for OS being preserved at around 90%. Prognostic relevance of CS-CTCs in PDAC was further validated in PB-samples from 228 PDAC patients, consolidating the established association between CTC-presence and reduced OS (8.5 vs. 19.0 months, p < 0.001). In conclusion, DLA-derived CS-CTCs may serve as a viable tool for identifying high-risk PDAC-patients and aiding the optimization of multimodal treatment strategies. Moreover, DLA enables comprehensive diagnostic profiling by providing ample CTC material, reinforcing its utility as a reliable liquid-biopsy approach. This high-volume liquid-biopsy strategy presents a potential pathway for enhancing clinical management in this malignancy.

Inverted Y-shaped technique for complex superior mesenteric / portal vein reconstruction in pancreatoduodenectomy for locally advanced pancreatic head ductal adenocarcinoma

Most pancreatoduodenectomy (PD) procedures for locally advanced pancreatic head adenocarcinoma (PDAC) require superior mesenteric/portal vein (SMV/PV) axis resection and reconstruction. Here we describe the inverted Y-shaped as a new technique for complex SMV/PV reconstruction and aimed at evaluating its safety and effectiveness. Among 287 patients who underwent PD for locally advanced PDAC from April, 2007 to December, 2020 at our hospital, 11 patients (3.8%) who underwent PV/SMV reconstruction with this technique were enrolled. Briefly, two distal veins were slit-wedged, sutured, resulting in one orifice, then reconstruction was completed with (n = 6) or without (n = 5) interposed autologous right external iliac vein (REIV) grafts, respectively. Operation time and blood loss were 649 (502-822) min and 1782 (475-6680) mL, respectively. The median length of resected SMV/PV was 40 (20-70) mm, 50 (50-70) mm for REIV grafts, and the splenic vein was resected in eight patients. No patient developed pancreatic fistula; mild leg edema was observed in the six graft patients and the median hospital stay was 36.0 d. PV patency rate at 2 mo after PD was 91% (10/11) and no 90-d mortality was recorded. R0 resection rate was 91% (10/11). It is feasible to safely reconstruct the SMV/PV using the inverted Y-shaped technique in appropriately selected PDAC patients.

Impact of Sarcopenia on Patients with Localized Pancreatic Ductal Adenocarcinoma Receiving FOLFIRINOX or Gemcitabine as Adjuvant Chemotherapy

Background: Despite its toxicity, modified FOLFIRINOX is the main chemotherapy for localized, operable pancreatic adenocarcinomas. Sarcopenia is known as a factor in lower overall survival (OS). The purpose of this study was to assess the impact of sarcopenia on OS in patients with localized pancreatic ductal adenocarcinoma (PDAC) who received modified FOLFIRINOX or gemcitabine as adjuvant chemotherapy. Methods: Patients with operated PDAC who received gemcitabine-based (GEM group) or oxaliplatin-based (OXA group) adjuvant chemotherapy between 2008 and 2021 were retrospectively included. Sarcopenia was estimated on a baseline computed tomography (CT) examination using the skeletal muscular index (SMI). The primary evaluation criterion was OS. Secondary evaluation criteria were disease-free survival (DFS) and toxicity. Results: Seventy patients treated with gemcitabine-based (n = 49) and oxaliplatin-based (n = 21) chemotherapy were included, with a total of fifteen sarcopenic patients (eight in the GEM group and seven in the OXA group). The median OS was shorter in sarcopenic patients (25 months) compared to non-sarcopenic patients (158 months) (p = 0.01). A longer OS was observed in GEM non-sarcopenic patients (158 months) compared to OXA sarcopenic patients (14.4 months) (p < 0.01). The median OS was 157.7 months in the GEM group vs. 34.1 months in the OXA group (p = 0.13). No differences in median DFS were found between the GEM group and OXA group. More toxicity events were observed in the OXA group (50%) than in the GEM group (10%), including vomiting (p = 0.02), mucositis (p = 0.01) and neuropathy (p = 0.01). Conclusion: Sarcopenia is associated with a worse prognosis in patients with localized operated PDAC whatever the delivered adjuvant chemotherapy.

Pancreatic cancer, radiomics and artificial intelligence

Patients with pancreatic ductal adenocarcinoma (PDAC) are generally classified into four categories based on contrast-enhanced CT at diagnosis: resectable, borderline resectable, unresectable, and metastatic disease. In the initial grading and staging of PDAC, structured radiological templates are useful but limited, as there is a need to define the aggressiveness and microscopic disease stage of these tumours to ensure adequate treatment allocation. Quantitative imaging analysis allows radiomics and dynamic imaging features to provide information of clinical outcomes, and to construct clinical models based on radiomics signatures or imaging phenotypes. These quantitative features may be used as prognostic and predictive biomarkers in clinical decision-making, enabling personalised management of advanced PDAC. Deep learning and convolutional neural networks also provide high level bioinformatics tools that can help define features associated with a given aspect of PDAC biology and aggressiveness, paving the way to define outcomes based on these features. Thus, the prediction of tumour phenotype, treatment response and patient prognosis may be feasible by using such comprehensive and integrated radiomics models. Despite these promising results, quantitative imaging is not ready for clinical implementation in PDAC. Limitations include the instability of metrics and lack of external validation. Large properly annotated datasets, including relevant semantic features (demographics, blood markers, genomics), image harmonisation, robust radiomics analysis, clinically significant tasks as outputs, comparisons with gold-standards (such as TNM or pretreatment classifications) and fully independent validation cohorts, will be required for the development of trustworthy radiomics and artificial intelligence solutions to predict PDAC aggressiveness in a clinical setting.

Ketogenic HMG-CoA lyase and its product β-hydroxybutyrate promote pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDA) tumor cells are deprived of oxygen and nutrients and therefore must adapt their metabolism to ensure proliferation. In some physiological states, cells rely on ketone bodies to satisfy their metabolic needs, especially during nutrient stress. Here, we show that PDA cells can activate ketone body metabolism and that β-hydroxybutyrate (βOHB) is an alternative cell-intrinsic or systemic fuel that can promote PDA growth and progression. PDA cells activate enzymes required for ketogenesis, utilizing various nutrients as carbon sources for ketone body formation. By assessing metabolic gene expression from spontaneously arising PDA tumors in mice, we find HMG-CoA lyase (HMGCL), involved in ketogenesis, to be among the most deregulated metabolic enzymes in PDA compared to normal pancreas. In vitro depletion of HMGCL impedes migration, tumor cell invasiveness, and anchorage-independent tumor sphere compaction. Moreover, disrupting HMGCL drastically decreases PDA tumor growth in vivo, while βOHB stimulates metastatic dissemination to the liver. These findings suggest that βOHB increases PDA aggressiveness and identify HMGCL and ketogenesis as metabolic targets for limiting PDA progression.

Autophagy Contributes to Metabolic Reprogramming and Therapeutic Resistance in Pancreatic Tumors

Metabolic reprogramming is a feature of cancers for which recent research has been particularly active, providing numerous insights into the mechanisms involved. It occurs across the entire cancer process, from development to resistance to therapies. Established tumors exhibit dependencies for metabolic pathways, constituting vulnerabilities that can be targeted in the clinic. This knowledge is of particular importance for cancers that are refractory to any therapeutic approach, such as Pancreatic Ductal Adenocarcinoma (PDAC). One of the metabolic pathways dysregulated in PDAC is autophagy, a survival process that feeds the tumor with recycled intracellular components, through both cell-autonomous (in tumor cells) and nonautonomous (from the local and distant environment) mechanisms. Autophagy is elevated in established PDAC tumors, contributing to aberrant proliferation and growth even in a nutrient-poor context. Critical elements link autophagy to PDAC including genetic alterations, mitochondrial metabolism, the tumor microenvironment (TME), and the immune system. Moreover, high autophagic activity in PDAC is markedly related to resistance to current therapies. In this context, combining autophagy inhibition with standard chemotherapy, and/or drugs targeting other vulnerabilities such as metabolic pathways or the immune response, is an ongoing clinical strategy for which there is still much to do through translational and multidisciplinary research.