Ex vivo modeling of acquired drug resistance in BRAF - mutated pancreatic cancer organoids uncovers individual therapeutic vulnerabilities.

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis due to late detection and limited treatment options. Some PDAC patients harbor alterations that qualify for targeted treatment strategies but develop acquired resistance, leading to treatment failure. We here report the ex vivo modeling of acquired drug resistance by creating a PDAC patient-derived tumor organoid (PDTO) model harboring a rare BRAF R506_K507ins VLR mutation resulting in a resistance to trametinib, a MEK inhibitor. Genomic and transcriptomic analyses revealed upregulated WNT signaling in resistant PDTO clones compared to treatment-naïve parental control cells. By combining genomic and transcriptomic analysis with a functional drug testing approach, we uncovered a de novo upregulation and circumventive reliance on WNT signaling in resistant PDTO clones. Ex vivo models such as PDTOs represent valuable tools for resistance modelling and offer the discovery of novel therapeutic approaches for patients in need where clinical diagnostic tools are currently at the limit.

Is Computed-Tomography-Based Body Composition a Reliable Predictor of Chemotherapy-Related Toxicity in Pancreatic Cancer Patients?

BACKGROUND: Malnutrition, loss of weight and of skeletal muscle mass are frequent in pancreatic cancer patients, a majority of which will undergo chemotherapy over the course of their disease. Available data suggest a negative prognostic role of these changes in body composition on disease outcomes; however, it is unclear whether tolerance to chemotherapeutic treatment is similarly and/or negatively affected. We aimed to explore this association by retrospectively assessing changes in body composition and chemotherapy-related toxicity in a cohort of advanced pancreatic cancer patients. METHODS: Body composition was evaluated through clinical parameters and through radiological assessment of muscle mass, skeletal muscle area, skeletal muscle index and skeletal muscle density; and an assessment of fat distribution by subcutaneous adipose tissue and visceral adipose tissue. We performed descriptive statistics, pre/post chemotherapy comparisons and uni- and multivariate analyses to assess the relation between changes in body composition and toxicity. RESULTS: Toxicity risk increased with an increase of skeletal muscle index (OR: 1.03) and body mass index (OR: 1.07), whereas it decreased with an increase in skeletal muscle density (OR: 0.96). Multivariate analyses confirmed a reduction in the risk of toxicity only with an increase in skeletal muscle density (OR: 0.96). CONCLUSIONS: This study suggests that the retrospective analysis of changes in body composition is unlikely to be useful to predict toxicity to gemcitabine-nab-paclitaxel.

BRAFΔß3-αC in-frame deletion mutants differ in their dimerization propensity, HSP90 dependence, and druggability.

In-frame BRAF exon 12 deletions are increasingly identified in various tumor types. The resultant BRAFΔß3-αC oncoproteins usually lack five amino acids in the ß3-αC helix linker and sometimes contain de novo insertions. The dimerization status of BRAFΔß3-αC oncoproteins, their precise pathomechanism, and their direct druggability by RAF inhibitors (RAFi) has been under debate. Here, we functionally characterize BRAFΔLNVTAP>F and two novel mutants, BRAFdelinsFS and BRAFΔLNVT>F, and compare them with other BRAFΔß3-αC oncoproteins. We show that BRAFΔß3-αC oncoproteins not only form stable homodimers and large multiprotein complexes but also require dimerization. Nevertheless, details matter as aromatic amino acids at the deletion junction of some BRAFΔß3-αC oncoproteins, e.g., BRAFΔLNVTAP>F, increase their stability and dimerization propensity while conferring resistance to monomer-favoring RAFi such as dabrafenib or HSP 90/CDC37 inhibition. In contrast, dimer-favoring inhibitors such as naporafenib inhibit all BRAFΔß3-αC mutants in cell lines and patient-derived organoids, suggesting that tumors driven by such oncoproteins are vulnerable to these compounds.

Retrospective Analysis of Treatment Pathways in Patients With BRAFV600E-mutant Metastatic Colorectal Carcinoma - MORSECRC.

BACKGROUND/AIM: Metastatic colorectal cancer (mCRC) is a heterogeneous disease with distinct molecular subtypes. The BRAFV600E-mutation found in approximately 8-12% of mCRC patients is associated with poor prognosis. Guideline recommendations for this population are mostly based on small cohorts due to lack of clinical data. This retrospective analysis was designed to evaluate (approved) therapeutic approaches and algorithms in BRAFV600E-mutant mCRC prior to approval of the targeted combination encorafenib plus cetuximab in Germany, Austria, and Switzerland. PATIENTS AND METHODS: Anonymized data from BRAFV600E-mutant mCRC patients were analyzed retrospectively regarding 1st-, 2nd- and 3rd-line treatment using descriptive statistics. RESULTS: Forty-two patients were eligible for analysis (mean age 62.1 years, 47.6% female). At initial diagnosis, 20 patients (47.6%) were documented with right-sided tumors. Most patients (81.0%) were tested for BRAF before 1st-line. Four patients (9.5%) showed high microsatellite instability (MSI-H). Based on 94 treatment lines, chemotherapy combined with targeted therapy (TT) was used mostly (61.7%), followed by chemotherapy alone (19.1%). Backbone therapies were most frequently FOLFOXIRI (27.7%), FOLFOX/CAPOX (22.3%), or FOLFIRI (20.2%). Anti-VEGF/VEGFR and anti-EGFR-treatments were used in 45.7% and 23.4% of patients, respectively. Across all treatment lines and types, the predominantly documented reason for discontinuation was lack of efficacy. CONCLUSION: Combined chemotherapy+TT (anti-VEGF/VEGFR and anti-EGFR) played a predominant role in BRAFV600E-mutated mCRC treatment prior to approval of the targeted combination encorafenib plus cetuximab. Since lack of efficacy was the major reason for treatment discontinuation, newly approved therapies including encorafenib plus cetuximab and - for MSI-H tumors - pembrolizumab represent urgently needed options for future mCRC patients.

Comprehensive Treatment Algorithms of the Swiss Peritoneal Cancer Group for Peritoneal Cancer of Gastrointestinal Origin.

Peritoneal cancer (PC) is a dire finding, yet in selected patients, long-term survival is possible. Complete cytoreductive surgery (CRS) together with combination immunochemotherapy is essential to achieve cure. Hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC) are increasingly added to the multimodal treatment. The Swiss Peritoneal Cancer Group (SPCG) is an interdisciplinary group of expert clinicians. It has developed comprehensive treatment algorithms for patients with PC from pseudomyxoma peritonei, peritoneal mesothelioma, gastric, and colorectal origin. They include multimodal neoadjuvant treatment, surgical resection, and palliative care. The indication for and results of CRS HIPEC and PIPAC are discussed in light of the current literature. Institutional volume and clinical expertise required to achieve best outcomes are underlined, while inclusion of patients considered for CRS HIPEC and PIPAC in a clinical registry is strongly advised. The present recommendations are in line with current international guidelines and provide the first comprehensive treatment proposal for patients with PC including intraperitoneal chemotherapy. The SPCG comprehensive treatment algorithms provide evidence-based guidance for the multimodal care of patients with PC of gastrointestinal origin that were endorsed by all Swiss clinicians routinely involved in the multimodal care of these challenging patients.

ROS1 genomic rearrangements are rare actionable drivers in microsatellite stable colorectal cancer.

c-Ros oncogene 1, receptor tyrosine kinase (ROS1) genomic rearrangements have been reported previously in rare cases of colorectal cancer (CRC), yet little is known about the frequency, molecular characteristics, and therapeutic vulnerabilities of ROS1-driven CRC. We analyzed a clinical dataset of 40 589 patients with CRC for ROS1 genomic rearrangements and their associated genomic characteristics (Foundation Medicine, Inc [FMI]). We moreover report the disease course and treatment response of an index patient with ROS1-rearranged metastatic CRC. ROS1 genomic rearrangements were identified in 34 (0.08%) CRC samples. GOPC-ROS1 was the most common ROS1 fusion identified (11 samples), followed by TTC28-ROS1 (3 samples). Four novel 5' gene partners of ROS1 were identified (MCM9, SRPK1, EPHA6, P4HA1). Contrary to previous reports on fusion-positive CRC, ROS1-rearrangements were found exclusively in microsatellite stable (MSS) CRCs. KRAS mutations were significantly less abundant in ROS1-rearranged vs ROS1 wild type cases. The index patient presented with chemotherapy-refractory metastatic right-sided colon cancer harboring GOPC-ROS1. Molecularly targeted treatment with crizotinib induced a rapid and sustained partial response. After 15 months on crizotinib disseminated tumor progression occurred and KRAS Q61H emerged in tissue and liquid biopsies. ROS1 rearrangements define a small, yet therapeutically actionable molecular subgroup of MSS CRC. In summary, the high prevalence of GOPC-ROS1 and noncanonical ROS1 fusions pose diagnostic challenges. We advocate NGS-based comprehensive molecular profiling of MSS CRCs that are wild type for RAS and BRAF and patient enrollment in precision trials.

Study Protocol for a Randomised Controlled Trial on Pulmonary Metastasectomy vs. Standard of Care in Colorectal Cancer Patients With ≥ 3 Lung Metastases (PUCC-Trial).

This is a multicentre prospective randomised controlled trial for patients with 3 or more resectable pulmonary metastases from colorectal carcinoma. The study investigates the effects of pulmonary metastasectomy in addition to standard medical treatment in comparison to standard medical treatment plus possible local ablative measures such as SBRT. This trial is intended to demonstrate an overall survival difference in the group undergoing pulmonary metastasectomy. Further secondary and exploratory endpoints include quality of life (EORTC QLQ-C30, QLQ-CR29 and QLQ-LC29 questionnaires), progression-free survival and impact of mutational status. Due to the heterogeneity and complexity of the disease and treatment trajectories in metastasised colorectal cancer, well powered trials have been very challenging to design and execute. The goal of this study is to create a setting which allows treatment as close to the real life conditions as possible but under well standardised conditions. Based on previous trials, in which patient recruitment in the given setting hindered successful study completion, we decided to (1) restrict inclusion to patients with 3 or more metastases (since in case of lesser, surgery will probably be the preferred option) and (2) allow for real world standard of care (SOC) treatment options before and after randomisation including watchful waiting (as opposed to a predefined treatment protocol) and (3) possibility that patient can receive SOC externally (to reduce patient burden). Moreover, we chose to stipulate 12 weeks of systemic treatment prior to possible resection to further standardize treatment response and disease course over a certain period of time. Hence, included patients will be in the disease state of oligopersistence rather than primary oligometastatic. The trial was registered in the German Clinical Trials Register (DRKS-No.: DRKS00024727).

Targeting ALK in Neuroendocrine Tumors of the Lung.

Background: Anaplastic lymphoma kinase (ALK) rearrangements are known oncogenic drivers in non-small cell lung cancer (NSCLC). Few case reports described the occurrence of such rearrangements in large cell neuroendocrine carcinomas (LCNECs) of the lung without information on clinical responses to ALK tyrosine kinase inhibitors (TKIs) in these cases. Currently, neuroendocrine tumors of the lungs are not screened for ALK rearrangements. Methods: To illustrate the clinical impact of molecular characterization in LCNECs, we report the disease course in three patients with ALK-rearranged metastatic LCNEC from our clinical routine, as well as their treatment response to ALK TKIs (index cases). To gain insight into the prevalence of ALK rearrangements in neuroendocrine tumors of the lung, we analyzed a retrospective cohort of 436 tumor biopsies including LCNEC (n = 61), small cell lung cancer (SCLC) (n = 206), typical (n = 91) and atypical (n = 69) carcinoids, and mixed histology (n = 9) for the presence of ALK rearrangements using a sequential diagnostic algorithm. ALK immunohistochemistry (IHC) was evaluable in 362 cases; fluorescence in situ hybridization (FISH) was evaluable in 28 out of the 35 IHC-positive cases, followed by next-generation sequencing (NGS) that was available in 12 cases. Results: Within the retrospective cohort, ALK IHC was positive in 35 out of 362 (9.7%) evaluable samples. FISH was positive in 3 out of the 28 (10.7%) evaluable cases: 2 with atypical carcinoids and 1 with LCNEC. Additionally, the 3 index cases showed positive ALK IHC, which was confirmed by NGS. Within the retrospective cohort, NGS confirmed the presence of an ALK genomic rearrangement in one FISH-positive atypical carcinoid where material was sufficient for sequencing. Two out of three patients with metastatic ALK-rearranged LCNEC received up-front treatment with the ALK TKI alectinib and showed rapid tumor response at all metastatic sites, including multiple brain metastases. Conclusions: ALK rearrangements represent rare but targetable oncogenic driver alterations in LCNEC. Contrarily to NSCLC, the detection of ALK rearrangements in neuroendocrine tumors of the lung is challenging, since ALK IHC can lead to false-positive results and therefore needs confirmation by FISH or NGS. Up-front comprehensive molecular profiling with NGS should be performed in metastatic LCNEC in order not to miss actionable genomic alterations.

Neoadjuvant Therapy for Resectable Pancreatic Cancer: A New Standard of Care. Pooled Data From 3 Randomized Controlled Trials.

OBJECTIVE: The aim of this study was to pool data from randomized controlled trials (RCT) limited to resectable pancreatic ductal adenocarcinoma (PDAC) to determine whether a neoadjuvant therapy impacts on disease-free survival (DFS) and surgical outcome. SUMMARY BACKGROUND DATA: Few underpowered studies have suggested benefits from neoadjuvant chemo (± radiation) for strictly resectable PDAC without offering conclusive recommendations. METHODS: Three RCTs were identified comparing neoadjuvant chemo (± radio) therapy vs. upfront surgery followed by adjuvant therapy in all cases. Data were pooled targeting DFS as primary endpoint, whereas overall survival (OS), postoperative morbidity, and mortality were investigated as secondary endpoints. Survival endpoints DFS and OS were compared using Cox proportional hazards regression with study-specific baseline hazards. RESULTS: A total of 130 patients were randomized (56 in the neoadjuvant and 74 in the control group). DFS was significantly longer in the neoadjuvant treatment group compared to surgery only [hazard ratio (HR) 0.6, 95% confidence interval (CI) 0.4-0.9] (P = 0.01). Furthermore, DFS for the subgroup of R0 resections was similarly longer in the neoadjuvant treated group (HR 0.6, 95% CI 0.35-0.9, P = 0.045). Although postoperative complications (Comprehensive Complication Index, CCI®) occurred less frequently (P = 0.008), patients after neoadjuvant therapy experienced a higher toxicity, but without negative impact on oncological or surgical outcome parameters. CONCLUSION: Neoadjuvant therapy can be offered as an acceptable standard of care for patients with purely resectable PDAC. Future research with the advances of precision oncology should now focus on the definition of the optimal regimen.

Commensal Clostridiales strains mediate effective anti-cancer immune response against solid tumors.

Despite overall success, T cell checkpoint inhibitors for cancer treatment are still only efficient in a minority of patients. Recently, intestinal microbiota was found to critically modulate anti-cancer immunity and therapy response. Here, we identify Clostridiales members of the gut microbiota associated with a lower tumor burden in mouse models of colorectal cancer (CRC). Interestingly, these commensal species are also significantly reduced in CRC patients compared with healthy controls. Oral application of a mix of four Clostridiales strains (CC4) in mice prevented and even successfully treated CRC as stand-alone therapy. This effect depended on intratumoral infiltration and activation of CD8+ T cells. Single application of Roseburia intestinalis or Anaerostipes caccae was even more effective than CC4. In a direct comparison, the CC4 mix supplementation outperformed anti-PD-1 therapy in mouse models of CRC and melanoma. Our findings provide a strong preclinical foundation for exploring gut bacteria as novel stand-alone therapy against solid tumors.

ß6-Integrin Serves as a Potential Serum Marker for Diagnosis and Prognosis of Pancreatic Adenocarcinoma.

INTRODUCTION: Despite enormous efforts during the past decades, pancreatic adenocarcinoma (PAC) remains one of the most deleterious cancer entities. A useful biomarker for early detection or prognosis of PAC does not yet exist. The goal of our study was the characterization of ß6-integrin (ITGB6) as a novel serum tumor marker for refined diagnosis and prognosis of PAC. Serum ITGB6 levels were analyzed in 3 independent PAC cohorts consisting of retrospectively and prospectively collected serum and/or (metastatic) PAC tissue specimens. METHODS: Using 2 independent cohorts, we measured serum ITGB6 concentrations in 10 chronic pancreatitis patients, 10 controls, as well as in 27 (cohort 1) and 24 (cohort 2) patients with PAC, respectively. In these patients, we investigated whether ITGB6 serum levels correlate with known clinical and prognostic markers for PAC and whether they might differ between patients with PAC or benign inflammatory diseases of the pancreas. RESULTS: We found that elevated serum ITGB6 levels (≥0.100 ng/mL) in patients suffering from metastasizing PAC presented an unfavorable prognostic outcome. By correlating the ITGB6 tissue expression in primary and metastatic PAC with clinical parameters, we found that positive ITGB6 expression in the tumor tissue is linked to increased serum ITGB6 levels in nonmetastatic PAC and correlates with carbohydrate antigen 19-9 and clinical outcome. DISCUSSION: Our findings suggest that ITGB6 might serve as a novel serum biomarker for early diagnosis and prognosis of PAC. Given the limited specificity and sensitivity of currently used carbohydrate antigen 19-9-based assays, ITGB6 may have the potential to improve the diagnostic accuracy for PAC.

Phase Ib dose-escalation study of the hypoxia-modifier Myo-inositol trispyrophosphate in patients with hepatopancreatobiliary tumors.

Hypoxia is prominent in solid tumors and a recognized driver of malignancy. Thus far, targeting tumor hypoxia has remained unsuccessful. Myo-inositol trispyrophosphate (ITPP) is a re-oxygenating compound without apparent toxicity. In preclinical models, ITPP potentiates the efficacy of subsequent chemotherapy through vascular normalization. Here, we report the results of an unrandomized, open-labeled, 3 + 3 dose-escalation phase Ib study (NCT02528526) including 28 patients with advanced primary hepatopancreatobiliary malignancies and liver metastases of colorectal cancer receiving nine 8h-infusions of ITPP over three weeks across eight dose levels (1'866-14'500 mg/m2/dose), followed by standard chemotherapy. Primary objectives are assessment of the safety and tolerability and establishment of the maximum tolerated dose, while secondary objectives include assessment of pharmacokinetics, antitumor activity via radiological evaluation and assessment of circulatory tumor-specific and angiogenic markers. The maximum tolerated dose is 12,390 mg/m2, and ITPP treatment results in 32 treatment-related toxicities (mostly hypercalcemia) that require little or no intervention. 52% of patients have morphological disease stabilization under ITPP monotherapy. Following subsequent chemotherapy, 10% show partial responses while 60% have stable disease. Decreases in angiogenic markers are noted in ∼60% of patients after ITPP and tend to correlate with responses and survival after chemotherapy.

Efficacy and side effects of immune checkpoint inhibitors in the treatment of colorectal cancer.

Colorectal cancers (CRCs) remain one of the most common and challenging neoplasia in the Western world. The response rate of immunotherapeutic treatment approaches in a subset of advanced CRCs is remarkable and has sustainably changed treatment regimens. Unfortunately, currently available immunotherapeutics only displayed significant antitumoral activity - in terms of progression free survival (PFS) and objective response rate (ORR) - in microsatellite instability-high (MSI-H)/DNA mismatch repair deficient (dMMR) CRCs. Subsequently, these remarkable results had led to the US Food and Drug Administration's approval of both immune checkpoint inhibitors (ICIs) pembrolizumab and nivolumab in the treatment of advanced MSI-H/dMMR CRCs. However, in microsatellite stable (MSS)/DNA mismatch repair proficient (pMMR) CRCs, ICIs have clearly failed to meet their expectations and are therefore not considered effective. As the vast majority of CRCs display a molecular MSS/pMMR profile, current treatment approaches endeavor to improve tumor immunogenicity that consecutively leads to increased proinflammatory cytokine levels as well as tumor infiltrating T-cells, which in turn may be targeted by various immunotherapeutic agents. Therefore, ongoing studies are investigating novel synergistic therapy modalities and approaches to overcome a "cold" to "hot" tumor conversion in MSS/pMMR CRCs. In this review, we summarize the efficacy and possible immune-related adverse events as well as novel therapeutic approaches of ICIs in the treatment of MSI-H/dMMR and MSS/pMMR CRCs.

Transitioning the Molecular Tumor Board from Proof of Concept to Clinical Routine: A German Single-Center Analysis.

Molecular precision oncology faces two major challenges: first, to identify relevant and actionable molecular variants in a rapidly changing field and second, to provide access to a broad patient population. Here, we report a four-year experience of the Molecular Tumor Board (MTB) of the Comprehensive Cancer Center Freiburg (Germany) including workflows and process optimizations. This retrospective single-center study includes data on 488 patients enrolled in the MTB from February 2015 through December 2018. Recommendations include individual molecular diagnostics, molecular stratified therapies, assessment of treatment adherence and patient outcomes including overall survival. The majority of MTB patients presented with stage IV oncologic malignancies (90.6%) and underwent an average of 2.1 previous lines of therapy. Individual diagnostic recommendations were given to 487 patients (99.8%). A treatment recommendation was given in 264 of all cases (54.1%) which included a molecularly matched treatment in 212 patients (43.4%). The 264 treatment recommendations were implemented in 76 patients (28.8%). Stable disease was observed in 19 patients (25.0%), 17 had partial response (22.4%) and five showed a complete remission (6.6%). An objective response was achieved in 28.9% of cases with implemented recommendations and for 4.5% of the total population (22 of 488 patients). By optimizing the MTB workflow, case-discussions per session increased significantly while treatment adherence and outcome remained stable over time. Our data demonstrate the feasibility and effectiveness of molecular-guided personalized therapy for cancer patients in a clinical routine setting showing a low but robust and durable disease control rate over time.

Sensitivity and Resistance of Oncogenic RAS-Driven Tumors to Dual MEK and ERK Inhibition.

Oncogenic mutations in RAS family genes arise frequently in metastatic human cancers. Here we developed new mouse and cellular models of oncogenic HrasG12V-driven undifferentiated pleomorphic sarcoma metastasis and of KrasG12D-driven pancreatic ductal adenocarcinoma metastasis. Through analyses of these cells and of human oncogenic KRAS-, NRAS- and BRAF-driven cancer cell lines we identified that resistance to single MEK inhibitor and ERK inhibitor treatments arise rapidly but combination therapy completely blocks the emergence of resistance. The prior evolution of resistance to either single agent frequently leads to resistance to dual treatment. Dual MEK inhibitor plus ERK inhibitor therapy shows anti-tumor efficacy in an HrasG12V-driven autochthonous sarcoma model but features of drug resistance in vivo were also evident. Array-based kinome activity profiling revealed an absence of common patterns of signaling rewiring in single or double MEK and ERK inhibitor resistant cells, showing that the development of resistance to downstream signaling inhibition in oncogenic RAS-driven tumors represents a heterogeneous process. Nonetheless, in some single and double MEK and ERK inhibitor resistant cell lines we identified newly acquired drug sensitivities. These may represent additional therapeutic targets in oncogenic RAS-driven tumors and provide general proof-of-principle that therapeutic vulnerabilities of drug resistant cells can be identified.

Treatment landscape of metastatic pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive form of cancer with a dismal prognosis. The lack of symptoms in the early phase of the disease makes early diagnosis challenging, and about 80-85% of the patients are diagnosed only after the disease is locally advanced or metastatic. The current front-line treatment landscape in local stages comprises surgical resection and adjuvant chemotherapy. In Switzerland, although both FOLFIRINOX and gemcitabine plus nab-paclitaxel regimens are feasible and comparable in the first-line setting, FOLFIRINOX is preferred in the treatment of fit (Eastern Cooperative Oncology Group [ECOG] performance status [PS]: 0-1), young (<65 years old) patients with few comorbidities and normal liver function, while gemcitabine plus nab-paclitaxel is used to treat less fit (ECOG PS: 1-2) and more vulnerable patients. In the second-line setting of advanced PDAC, there is currently only one approved regimen, based on the phase III NAPOLI-1 trial. Furthermore, the use of liposomal-irinotecan in the second line is supported by real-world data. Beyond the standard of care, various alternative treatment modalities are being explored in clinical studies. Immunotherapy has demonstrated only limited benefits until now, and only in cases of high microsatellite instability (MSI-H). However, data on the benefit of poly (ADP-ribose) polymerase (PARP) inhibition as maintenance therapy in patients with germline BRCA-mutated tumors might signal of an advance in targeted therapy. Currently, there is a lack of molecular and genetic biomarkers for optimal stratification of patients and in guiding treatment decisions. Thus, identification of predictive and prognostic biomarkers and evaluating novel treatment strategies are equally relevant for improving the prognosis of metastatic pancreatic cancer patients.

Plasma biomarkers for prediction of early tumor recurrence after resection of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a disease with a very unfavorable prognosis. Surgical resection represents the only potentially curative treatment option, but recurrence after complete resection is almost certain. In an exploratory attempt we here aimed at identifying preoperative plasma protein biomarkers with the potential to predict early recurrence after resection of PDAC. Peripheral blood samples from 14 PDAC patients divided into three groups according to their time to tumor recurrence after curatively intended resection (early: < 6 months, medium: 6-12 months, late: > 12 months) underwent targeted proteome analysis. Proteins most strongly discriminating early and late recurrence were then examined in a number of established PDAC cell lines and their culture supernatants. Finally, PDAC organoid lines from primary tumors of patients with early and late recurrence were analyzed for confirmation and validation of results. In total, 23 proteins showed differential abundance in perioperative plasma from PDAC patients with early recurrence when compared to patients with late recurrence. Following confirmation of expression on a transcriptional and translational level in PDAC cell lines we further focused on three upregulated (MAEA, NT5E, AZU1) and two downregulated proteins (ATP6AP2, MICA). Increased expression of NT5E was confirmed in a subset of PDAC organoid cultures from tumors with early recurrence. MICA expression was heterogeneous and ATP6AP2 levels were very similar in both organoids from early and late recurrent tumors. Most strikingly, we observed high MAEA expression in all tested PDAC (n = 7) compared to a non-cancer ductal organoid line. MAEA also demonstrated potential to discriminate early recurrence from late recurrence PDAC organoids. Our study suggests that identification of plasma protein biomarkers released by tumor cells may be feasible and of value to predict the clinical course of patients. Prediction of recurrence dynamics would help to stratify up-front resectable PDAC patients for neoadjuvant chemotherapy approaches in an individualized fashion. Here, MAEA and NT5E were the most promising candidates for further evaluation.

Multimodal treatment strategies for colorectal liver metastases.

Colorectal cancer is the third most common cancer worldwide. Half of CRC patients develop liver metastases during the course of the disease, with a 5-year survival rate close to zero in the absence of therapy. Surgical resection remains the only possible curative option, and current guidelines recommend adjuvant chemotherapy, resulting in a 5-year survival rate exceeding 50%. Neoadjuvant systemic therapy is not indicated in cases with simple resection but should be offered to all patients with extensive bilobar disease. Personalised systemic treatment is essential to convert upfront non-resectable lesions to resectable ones. Anatomical resections, non-anatomical resections and two-stage hepatectomies can be performed though open or minimally invasive (laparoscopic or robotic) surgery. The extent of a hepatic resection is limited by the risk of postoperative liver failure due to a too small liver remnant, inflow or outflow obstruction or insufficient biliary drainage. About 75% of patients are diagnosed with non-resectable liver metastases not amenable to a standard upfront resection. In recent years, effective therapeutic approaches have revolutionised liver surgery and new strategies have enabled the conversion of primarily non-resectable metastatic disease for resection. These strategies include oncological and surgical therapies, as well as combinations of the two. From an oncological perspective, colorectal liver metastases  may be treated by systemic chemotherapy or immunotherapy, or selective intra-hepatic arterial infusion chemotherapy, depending on the extent of the disease and the mutational status. In surgery, we often apply two-stage strategies using portal vein occlusion, such as portal vein embolisation or ligation, or complex two-stage hepatectomy such as associating liver partition and portal vein ligation for staged hepatectomy. Other additive tools to reach curative resection are tumour ablations (electroporation, microwave or radiofrequency). The role of stereotactic radiation of liver metastases is not yet well defined. Modern radiation techniques, including image guidance, breath hold and gating, were only introduced for a larger patient population in recent years. Therefore, prospective studies with larger patient cohorts are still pending. Over the last decade, liver transplantation has gained increasing attention in selective cases of non-resectable colorectal liver metastases, with promising cohort studies, but definitive recommendations must await the results of ongoing randomised controlled trials. The optimal treatment of patients with colorectal liver metastases requires the timely association of various strategies, and all cases must be discussed at multidisciplinary team conferences. While colorectal liver metastases was a uniformly lethal condition a few decades ago, it has become amenable to curative therapies, with excellent quality of life in many scenarios. This review reports on up-to-date treatment modalities and their combinations in the treatment algorithm of colorectal liver metastases.    .

Longitudinal analysis of cell-free mutated KRAS and CA 19-9 predicts survival following curative resection of pancreatic cancer.

BACKGROUND: Novel biomarkers and molecular monitoring tools hold potential to improve outcome for patients following resection of pancreatic ductal adenocarcinoma (PDAC). We hypothesized that the combined longitudinal analysis of mutated cell-free plasma KRAS (cfKRASmut) and CA 19-9 during adjuvant treatment and follow-up might more accurately predict disease course than hitherto available parameters. METHODS: Between 07/2015 and 10/2018, we collected 134 plasma samples from 25 patients after R0/R1-resection of PDAC during adjuvant chemotherapy and post-treatment surveillance at our institution. Highly sensitive discriminatory multi-target ddPCR assays were employed to screen plasma samples for cfKRASmut. cfKRASmut and CA 19-9 dynamics were correlated with recurrence-free survival (RFS) and overall survival (OS). Patients were followed-up until 01/2020. RESULTS: Out of 25 enrolled patients, 76% had undergone R0 resection and 48% of resected PDACs were pN0. 17/25 (68%) of patients underwent adjuvant chemotherapy. Median follow-up was 22.0 months, with 19 out of 25 (76%) patients relapsing during study period. Median RFS was 10.0 months, median OS was 22.0 months. Out of clinicopathologic variables, only postoperative CA 19-9 levels and administration of adjuvant chemotherapy correlated with survival endpoints. cfKRASmut. was detected in 12/25 (48%) of patients, and detection of high levels inversely correlated with survival endpoint. Integration of cfKRASmut and CA 19-9 levels outperformed either individual marker. cfKRASmut outperformed CA 19-9 as dynamic marker since increase during adjuvant chemotherapy and follow-up was highly predictive of early relapse and poor OS. CONCLUSIONS: Integrated analysis of cfKRASmut and CA 19-9 levels is a promising approach for molecular monitoring of patients following resection of PDAC. Larger prospective studies are needed to further develop this approach and dissect each marker's specific potential.