Dirk Walter

Introduction: IDH1 mutations occur in approximately 10%–20% of intrahepatic cholangiocarcinoma (iCCA) and constitute an established target for molecularly guided therapy. As routine molecular diagnostics are commonly based on a single tumour sample, intratumoral heterogeneity could affect the reliable detection of actionable mutations. This study assessed the spatial heterogeneity of IDH1 mutations in iCCA. Methods: Patients with histologically confirmed iCCA who underwent routine next‐generation sequencing (NGS) and had multiple available formalin‐fixed paraffin‐embedded (FFPE) tumour samples were retrospectively analysed. Baseline IDH1 status was determined by NGS. All available tumour regions were subsequently tested using the Idylla™ IDH1‐2 Mutation Assay. Blocks where the Idylla™ IDH1 mutational status was discordant with baseline status were validated by digital polymerase chain reaction (dPCR). Results: Thirty‐five patients with iCCA were included, yielding 117 FFPE samples from spatially distinct tumour regions. Baseline NGS identified IDH1 mutations in 22.8% (8/35) of patients. Idylla™ testing revealed discordant results in 5 of 117 samples (4.2%). Validation by dPCR demonstrated that these discordances were attributable to technical limitations or assay‐related errors rather than true biological heterogeneity. Following validation, all IDH1‐mutated tumours showed concordant mutation status across all analysed tumour regions. Conclusions: IDH1 mutations appear to be spatially homogeneous in iCCA, supporting their role as an early clonal event. These findings indicate that single‐sample molecular testing is sufficient for reliable determination of IDH1 status and patient selection for IDH1‐targeted therapies.

Purpose: The newly discovered histone methyltransferase KMT9 serves as an epigenetic regulator of carcinogenesis in various cancer entities. For the first time, we investigated the presence of KMT9α in cholangiocarcinoma, the association with histologic subtypes, and its impact on survival. Methods: A tissue microarray cohort of all CCA patients who underwent surgical resection with curative intent between 08/2005 and 12/2021 at the University Hospital Frankfurt was immunohistochemically analyzed with the KMT9α antibody. For overall survival, Kaplan–Meier curves and Cox-regression analyses were performed. Results: In total, 174 patients were suitable for IHC analysis. Of the patients, 35.1% (n = 61) overexpressed KMT9α. Kaplan-Meier curves revealed a median OS of 34.75 months (95% CI = 20.23–49.27 months) for all CCA patients positive for KMT9α in comparison to 54.21 months (95% CI = 41.78–66.63 months) for patients lacking KMT9α overexpression (p = 0.004). Subtype analysis revealed strong differences in KMT9α expression. Multivariate Cox regression analysis identified KMT9α as an independent risk factor for shorter OS in CCA. Conclusion: This study demonstrates that a marked subset of CCA patients exhibit overexpression of KMT9α. These findings underscore the prognostic significance of KMT9α and reinforce its potential as a therapeutic target, consistent with its role in other cancer types.

Introduction: Treating biliary obstruction remains a common clinical problem. Endoscopic retrograde cholangiopancreatography (ERCP) with stent insertion remains the gold standard. If ERCP fails, percutaneous transhepatic biliary drainage (PTBD) is one treatment option. Despite a high success rate, early- and late-onset complications occur frequently, ranging from 20 to 70%. With this study, we aimed to provide further insights on possible risk factors for PTBD-related complications. Methods: All cases with PTBD placement at our institution over the past 13 years were retrospectively analyzed and median premature exchange rate as well as procedural-associated complications were determined. Results: A total of 976 PTBDs were inserted in 194 patients. In 853 cases (87%), only one PTBD was inserted. Most patients had a benign disease as an indication for the PTBD insertion (n = 558 cases, 56.9%). A premature PTBD exchange occurred in 246 cases (26%). The most common reason for a premature PTBD exchange or extraction was dislocation (n = 98/39.5%), followed by cholangitis in 70 cases (28.6%). A malignant indication (multivariate p = 0.001 OR = 1.69 95% CI = 1.23–2.30), female sex (multivariate p < 0.001 OR = 2.21 95% CI = 1.56–3.12), and a PTBD ≥14Fr (multivariate p < 0.03 1.50 (1.04–2.11) were associated with a premature stent exchange in the mixed multivariate regression analysis. Conclusion: Premature exchanges occur frequently in patients treated with PTBD. Especially in patients with malignancy, other interventional bile drainage interventions should be discussed. In case PTBD is chosen, earlier exchange rates than 12 weeks should be considered.

Aims: Anti‐claudin‐18.2 (CLDN18.2) therapy was recently approved for the treatment of gastric or gastro‐oesophageal junction adenocarcinoma. The aim of the present study was to investigate the expression of CLDN18.2 in cholangiocarcinoma (CCA) to determine whether there is a subgroup of patients who might also benefit from anti‐CLDN18.2 therapy.Methods and results: A tissue microarray (TMA) cohort of all CCA patients who underwent surgical resection with curative intent between August 2005 and December 2021 at University Hospital Frankfurt were immunohistochemically evaluated using the VENTANA^® CLDN18 (43‐14A) antibody. Tumour positivity for CLDN18.2 was determined as follows: ≥ 75% of tumour cells with moderate‐to‐strong CLDN18 membranous staining. In total, 160 patients with surgically resected CCA were suitable for immunohistochemistry (IHC) analysis. Of the patients, 13.1% (n = 21) showed moderate to strong membranous staining of VENTANA^® CLDN18 antibody, while 86.9% (n = 139) were negative. Subtype analysis revealed strong differences in CLDN18 expression. Positive staining of CLDN18 could be observed in 26.5% (n = nine of 34) and 7.4% (n = seven of 95) of the perihilar (pCCA) and intrahepatic (iCCA) subgroup, respectively. CCA patients with CLDN18 expression had a more frequently intraoperative finding of distant metastasis (P = 0.002), lymph node metastasis (P = 0.008) and positive perineural invasion (Pn1) status (P = 0.022).Conclusions: The present study suggests that a subset of patients with CCA exhibited a marked expression of CLDN18.2. These findings underline the need to perform a clinical study evaluating the efficacy of anti‐CLDN18.2 therapy in patients suffering from CCA.

INTRODUCTION: International guidelines suggest different possibilities for drying of endoscopes during reprocessing. Clinical results of these available drying methods are not satisfactory. The aim of this study was to compare the drying cycle of a standard endoscope washer-disinfector (EWD) (standard drying method [SD]) with a shortened mandatory drying by the EWD followed by a special drying device using laminar and turbulent air flow (novel drying method [ND]). METHODS: Sixty endoscopes (duodenoscopes, colonoscocopes, and gastroscopes) from 3 different manufacturers underwent high-level disinfection and drying depending on the randomization group. Operational time of drying was measured for both groups. Residual fluid in the channels was measured using a laboratory scale. After a 14-day storage period, a sample of the endoscope channels was obtained to determine bacterial contamination. RESULTS: ND had significantly fewer residual water in endoscope channels (SD: 90% vs ND: 0%; P < 0.001) after high-level disinfection and drying and less bacterial contamination after storage for 14 days (SD: 47% vs ND: 20%; P = 0.028). Time consumed for drying in ND was also significantly shorter (SD: 16 minutes 4 seconds vs ND: 5 minutes 59 seconds; P < 0.001). DISCUSSION: Drying with a special automatic drying device was superior compared with an EWD's drying program as evidenced by no measurable residual water, reduced microbiological contamination, and a more than 2-fold decrease in operational time. Thus, drying by laminar and turbulent airflow may represent an attractive alternative to the currently used standard approach in the reprocessing process of flexible endoscopes.

Purpose: Dedicated gene signatures in small (SD-iCCA) and large (LD-iCCA) duct type intrahepatic cholangiocarcinoma remain unknown. We performed immune profiling in SD- and LD-iCCA to identify novel biomarker candidates for personalized medicine. Methods: Retrospectively, 19 iCCA patients with either SD-iCCA (n = 10, median age, 63.1 years (45–86); men, 4) or LD-iCCA (n = 9, median age, 69.7 years (62–85); men, 5)) were included. All patients were diagnosed and histologically confirmed between 04/2009 and 01/2021. Tumor tissue samples were processed for differential expression profiling using NanoString nCounter® PanCancer Immune Profiling Panel. Results: With the exception of complement signatures, immune-related pathways were broadly downregulated in SD-iCCA vs. LD-iCCA. A total of 20 immune-related genes were strongly downregulated in SD-iCCA with DMBT1 (log2fc = -5.39, p = 0.01) and CEACAM6 (log2fc = -6.38, p = 0.01) showing the strongest downregulation. Among 7 strongly (log2fc > 2, p ≤ 0.02) upregulated genes, CRP (log2fc = 5.06, p = 0.02) ranked first, and four others were associated with complement (C5, C4BPA, C8A, C8B). Total tumor-infiltrating lymphocytes (TIL) signature was decreased in SD-iCCA with elevated ratios of exhausted-CD8/TILs, NK/TILs, and cytotoxic cells/TILs while having decreased ratios of B-cells/TILs, mast cells/TILs and dendritic cells/TILs. The immune profiling signatures in SD-iCCA revealed downregulation in chemokine signaling pathways inclulding JAK2/3 and ERK1/2 as well as nearly all cytokine-cytokine receptor interaction pathways with the exception of the CXCL1/CXCR1-axis. Conclusion: Immune patterns differed in SD-iCCA versus LD-iCCA. We identified potential biomarker candidate genes, including CRP, CEACAM6, DMBT1, and various complement factors that could be explored for augmented diagnostics and treatment decision-making.

Aims: The histological subtype of intrahepatic cholangiocarcinoma (iCCA) is associated with different mutational characteristics that impact clinical management. So far, data are lacking on the presence of small duct iCCA (SD‐iCCA) and large duct iCCA (LD‐iCCA) in a single patient. The aim of the current study was to determine the presence and degree of intratumoural heterogeneity of SD‐ and LD‐iCCA features in different tumour regions.Methods and results: All patients treated with surgically resected iCCA at Frankfurt University Hospital between December 2005 and March 2023 were retrospectively analysed. Histomorphological features of SD‐ and LD‐iCCA were evaluated by an expert hepatobiliary pathologist. Tissue samples suspicious for subtype heterogeneity were further investigated. Immunohistochemistry for N‐cadherin, S100P, MUC5AC, MUC6, TFF1 and AGR2 and mutational profiling with the Illumina TruSight Oncology 500 (TSO500) assay were performed separately for the SD‐ and LD‐iCCA regions. Of 129 patients with surgically resected iCCA, features of either SD‐ or LD‐iCCA were present in 67.4% (n = 87) and 24.8% of the patients (n = 32), respectively; 7.8% (n = 10) had histomorphological features of both SD‐ and LD‐iCCA, seven patients (5.4%) of which had sufficient formalin‐fixed, paraffin‐embedded tissue for further analysis. Heterogeneity of both subtypes could be confirmed with immunohistochemistry. In five of seven (71.4%) patients, molecular profiling revealed intratumoural differences in genetic alterations between the SD‐ and LD‐iCCA region. In one patient, a BRAF mutation (p.V600E) was found in the SD‐iCCA but not in the LD‐iCCA region of the tumour.Conclusions: A marked portion of patients with iCCA exhibits both SD‐ and LD‐iCCA in different tumour regions. In case of the presence of histopathological heterogeneity, mutational profiling should be considered to avoid missing therapeutically relevant genetic alterations.

Background: Ampullary or papillary carcinoma is a malignant tumor arising from the mucosa in the region of the major duodenal papilla, also known as the ampulla of Vater. Uniform treatment recommendations are lacking both for the adjuvant situation and for palliative care.Methods: A selective literature search was carried out in PubMed in order to identify the most informative publications concerning the epidemiology, clinicopathological background, and surgical and medical treatment of this condition.Results: Ampullary carcinoma has an incidence of 0.5 to 0.9 per 100 000 persons and a poor prognosis, with a 5-year survival rate of 41% to 45% for locally confined and 4% to 7% for metastatic disease. Most such tumors are of an intestinal or a pan creaticobiliary immunohistochemical subtype; the latter has a worse prognosis (median survival, 72-80 vs. 33-41 months). Targeted treatment is not yet available for either subtype, nor is there enough scientific evidence available for the formulation of specific therapeutic recommendations in either the adjuvant or the palliative situation. The treatment of choice for ampullary carcinoma is radical oncological resection of the head of the pancreas with systematic lymphadenectomy. Five-year overall survival is between 10% and 75% depending on the stage. No definitive recommendation for adjuvant therapy can be given. Palliative therapy can be oriented to the published treatment strategies for cancer of the colon, pancreas, and bile duct.Conclusion: The current state of the evidence on the treatment of ampullary carcinoma is poor. Therapeutic decisions should be discussed in an interdisciplinary tumor board and should, in our opinion, take the histological subtype into account.

Malignancies can cause severe stenosis of the biliary tract and therefore predispose a patient to bacterial cholangitis. Upon endoscopic drainage, antibiotic therapy (AT) is performed according to individual clinical judgement, as the optimal duration of AT is unclear to date, especially in the case of multidrug-resistant organisms (MDROs). In a case-based retrospective study, patients with malignant biliary strictures and acute cholangitis were included upon endoscopic retrograde cholangiography (ERC). The outcome of cases treated with short AT (≤6 days) was compared to that of long AT (≥7 days). Recurrent cholangitis (RC) before scheduled stent exchange was the primary end point. In total, 124 patients were included, with 183 cases of proven cholangitis in total. The overall median duration of AT was 7 days (range 1–20), with 74 cases (40%) receiving short AT and 109 (60%) receiving long AT. Short AT was not an independent risk factor for RC (HR = 0.66, p > 0.2), while colonization with MDROs was associated with a higher risk of RC (HR = 2.21, p = 0.005). Placement of a metal stent was associated with minor risk of RC (HR = 0.4, p = 0.038). In conclusion, short AT is possible in selected patients with non-severe cholangitis and malignant biliary strictures. Scheduled screening for MDROs is recommended and placement of a metal stent should be performed if possible.