BackgroundMerkel cell carcinoma (MCC) is associated with high recurrence rates and poor survival when metastatic disease is present. The immune checkpoint inhibitor avelumab has shown high response rates (RRs) and durable responses in patients with advanced MCC (aMCC) in clinical trials. To date, only results from clinical trials, patients treated in an expanded access program and very small numbers of patients have been reported. In this study, detailed real-world efficacy and toxicity data of avelumab in patients with aMCC are reported.MethodsPatients with aMCC treated in four dedicated referral centers in the Netherlands were analyzed from February 2017 until December 2019. Patients were included if they had received at least one administration of avelumab, regardless of previous lines of therapy. Patient data were collected retrospectively from patient records. Primary endpoints were response rate (RR) and duration of response (DOR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicity.ResultsFifty-four patients received avelumab. Eight (15%) patients had locally advanced disease (laMCC). In 40 (74%) patients, avelumab was first-line treatment, these included all patients with laMCC. The median follow-up was 8.9 (range 0.5–35.9) months. RR was 57% (n=31) with 24% (n=13) of patients achieving a complete response. The median DOR was 8.4 (range 1.3–22.1) months and 23 (43%) patients had an ongoing response at the end of the study. The median PFS was 8.6 (95% CI 1.6–15.5) months, and the median OS was 25.8 (95% CI 9.1–42.4) months. Six (11%) patients experienced grade 3 toxicity. No grade 4–5 toxicity was seen.ConclusionsIn this real-world cohort, clinical efficacy and toxicity outcomes in clinical practice were in line with results from clinical trials and showed relatively high RRs and durable responses in patients with aMCC.

Neuroendocrine tumours of the small intestine (SI-NETs) are rare and heterogeneous. There is an unmet need for prognostication of disease course and to aid treatment strategies. A previously developed nomogram based on clinical and tumour characteristics aims to predict disease-specific survival (DSS) in patients with a SI-NET. We aimed to validate the nomogram and identify predictors of survival. Four hundred patients with a grade 1 or 2 SI-NET were included, between January 2000 and June 2016. Predicted 5- and 10-year survival was compared to actual DSS. Multivariable analysis identified predictors for actual DSS. We found that in low-, medium- and high-risk groups 5-year nomogram DSS vs. actual DSS was 0.86 vs. 0.82 (p < 0.001), 0.52 vs. 0.71 (p < 0.001) and 0.26 vs. 0.53 (p < 0.001), respectively. Ten-year nomogram DSS vs. actual DSS was 0.68 vs. 0.69 (p < 0.001), 0.40 vs. 0.50 (p < 0.001) and 0.20 vs. 0.35 (p < 0.001), respectively. Age, WHO-performance score of 2, Ki-67 index ≥10, unknown primary tumour, CgA > 6x ULN and elevated liver tests were identified as independent predictors for a worse DSS. This shows that the nomogram was able to differentiate, but underestimated DSS for patients with a SI-NET. Improvement of prognostication incorporating new emerging biomarkers is necessary to adequately estimate survival.

Carcinoid heart disease (CHD) is a rare fibrotic cardiac complication of neuroendocrine tumors. Besides known biomarkers N-Terminal pro-B-type natriuretic peptide (NT-proBNP) and serotonin, activin A, connective tissue growth factor (CTGF), and soluble suppression of tumorigenicity 2 (sST2) have been suggested as potential biomarkers for CHD. Here, we validated the predictive/diagnostic value of these biomarkers in a case-control study of 114 patients between 1990 and 2021. Two time-points were analyzed: T0: liver metastasis without CHD for all patients. T1: confirmed CHD in cases (CHD+, n = 57); confirmed absence of CHD five or more years after liver metastasis in controls (CHD–, n = 57). Thirty-one (54%) and 25 (44%) females were included in CHD+ and CHD– patients, respectively. Median age was 57.9 years for CHD+ and 59.7 for CHD- patients (p = 0.290). At T0: activin A was similar across both groups (p = 0.724); NT-proBNP was higher in CHD+ patients (17 vs. 6 pmol/L, p = 0.016), area under the curve (AUC) 0.84, and the most optimal cut-off at 6.5 pmol/L. At T1: activin A was higher in CHD+ patients (0.65 vs. 0.38 ng/mL, p = 0.045), AUC 0.62, without an optimal cut-off value. NT-pro-BNP was higher in CHD+ patients (63 vs. 11 pmol/L, p < 0.001), AUC 0.89, with an optimal cut-off of 27 pmol/L. Serotonin (p = 0.345), sST2 (p = 0.867) and CTGF (p = 0.232) levels were similar across groups. This large validation study identified NT-proBNP as the superior biomarker for CHD. Patients with elevated serotonin levels and NT-proBNP levels between 6.5 and 27 pmol/L, and specifically >27 pmol/L, should be monitored closely for the development of CHD.

Carcinoid heart disease (CHD) is a serious cardiac condition which is caused by elevated serotonin in the systemic circulation, secreted by neuroendocrine tumours (NET). It mostly affects the right-sided heart valves, where it causes fibrotic disturbances and is associated with worse survival. In this study, we describe a large cohort of patients with CHD and provide an insight into their survival over the past decades.All consecutive patients with a serotonin producing NET and CHD referred to the Netherlands Cancer Institute that presented with CHD or developed CHD during their follow up time were included from 1984 until 2021. Patients were divided into three

ObjectiveSudden cardiac death (SCD) in families with premature atherosclerosis (PAS) is generally attributed to lethal arrhythmias during myocardial infarction. Yet, such arrhythmias may also arise from non-ischaemic inherited susceptibility. We aimed to test the hypothesis that Brugada syndrome is prevalent among families with PAS in which SCD occurred.MethodsWe investigated all patients who underwent Ajmaline testing to screen them for Brugada syndrome because of unexplained familial SCD in the Amsterdam University Medical Centers between 2004 and 2017. We divided the cohort into two groups based on a positive family history for PAS. All individuals with a positive Ajmaline test were screened for SCN5A-mutation.ResultsIn families with SCD and PAS, the prevalence of positive Ajmaline test was similar to families with SCD alone (22% vs 19%). The number of SCD cases in families with SCD and PAS was higher (2.34 vs 1.63, p<0.001) and SCD occurred at older age in families with SCD and PAS (42 years vs 36 years, p<0.001), while the prevalence of SCN5A mutations was lower (3% vs 18%, p<0.05).ConclusionsBrugada syndrome has a similar prevalence in families with SCD and PAS as in families with SCD alone, although SCD in families with SCD and PAS occurs in more family members and at older age, while SCN5A mutations in these families are rare. This suggests that the SCD occurring in families with PAS could be related to an underlying genetic predisposition of arrhythmias, with a different genetic origin. It could be considered to screen families with SCD and PAS for Brugada syndrome.

Aims To investigate the clinicopathological significance of driver mutations in metastatic well‐differentiated small intestine neuroendocrine tumours (SI‐NETs). Methods and results Whole genome sequencing (WGS) of 35 metastatic SI‐NETs and next‐generation sequencing (NGS) of eight metastatic SI‐NETs were performed. Biopsies were obtained between 2015 and 2019. Tumours were classified according to the 2019 World Health Organization classification. WGS included assessment of somatic mutations in all cancer‐related driver genes, the tumour mutational burden (TMB), and microsatellite status. NGS entailed a cancer hotspot panel of 58 genes. Our cohort consisted of 21% grade 1, 60% grade 2 and 19% grade 3 SI‐NETs. Driver mutations were identified in ~50% of SI‐NETs. In total, 27 driver mutations were identified, of which 74% were in tumour suppressor genes (e.g. TP53, RB1, and CDKN1B) and 22% were in proto‐oncogenes (e.g. KRAS, NRAS, and MET). Allelic loss of chromosome 18 (63%), complete loss of CDKN2A and CDKN1B (both 6%) and CDKN1B mutations (9%) were most common. Potential targetable genetic alterations were detected in 21% of metastasised SI‐NETs. All tumours were microsatellite‐stable and showed low TMBs (median 1.10; interquartile range 0.87–1.35). The Ki67 proliferation index was significantly associated with the presence of driver mutations (P = 0.015). Conclusion Driver mutations occur in 50% of metastasised SI‐NETs, and their presence is associated with a high Ki67 proliferation index. The identification of targetable mutations make these patients potentially eligible for targeted therapy.

Introduction: Until now, well-differentiated bronchopulmonary neuroendocrine tumors (bpNET) occurring either sporadically (sp-bpNET) or in the context of multiple endocrine neoplasia type 1 (MEN1) and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) are regarded as similar entities. However, in contrast to sp-bpNET: MEN1-related and DIPNECH-related bpNET rarely metastasize or lead to bpNET-related death. We aimed to describe and compare the course of the disease of sp-bpNET, DIPNECH-and MEN1-related bpNET.Methods: All patients with histologically confirmed MEN1-related bpNET from the DutchMEN Study Group database , patients with resected sp-bpNET and DIPNECH patients referred to a Dutch European Neuroendocrine Tumor Society center between 2000 and 2018 were included. Fisher's exact test was used for comparison between groups. The primary end point was disease-specific mortality (DSM). Kaplan-Meier and logrank test were used to compare survival. Cox regression was used to identify risk factors for DSM in the sp-bpNET subgroup.Results: We included 112 sp-bpNET, 29 MEN1, and 27 DIPNECH patients. Tumor classification was similar across subgroups. A total of 20 patients (18%) with sp-bpNET died because of bpNET, compared with none in the MEN1 group and DIPNECH group. Median disease-specific survival was 12.3 (confidence interval: 6.3-18.3) years for patients with sp-bpNET, and not estimable for the other subgroups (p < 0.001). Differences in baseline characteristics did not explain worse survival in sp-bpNET. Tumor classification and age at diagnosis were independent risk factors for DSM in sp-bpNET.Conclusions: Patients with sp-bpNET have a significantly higher DSM compared with MEN1 or DIPNECH-related bpNET, unexplained by differences in baseline characteristics. This implies that not all bpNET are similar entities.

Background: Extrapulmonary neuroendocrine carcinoma (EP-NEC) are an aggressive subgroup of neuroendocrine neoplasms (NEN). Advanced EP-NEC is generally treated with platinum-based cytotoxic regimens, but progressive disease occurs rapidly, resulting in a poor prognosis. Genetic alterations in the mammalian target for rapamycin (mTOR) pathway have been identified in NEN, providing a rationale for treatment with the mTOR-inhibitor everolimus. Methods: A prospective phase 2 single-arm study included patients with advanced EP-NEC from three Dutch NEN expertise centres between March 2016 and January 2020. Treatment consisted of cisplatin 75 mg/m2 every 3 weeks in combination with daily everolimus 7.5 mg for a maximum of six cycles, followed by maintenance everolimus until disease progression. Primary endpoint was disease control rate (DCR), defined as the sum of overall response rate (ORR) plus the rate of stable disease according to RECIST 1.1, assessed at 9-week intervals. Toxicity was evaluated according to CTCAE version 5.0. Results: Thirty-nine patients, with a median age of 64 years (range: 28–74), of whom 20 (51%) were male, were enrolled. DCR was 82.1% (95% confidence interval (CI): 66.4–92.4), with an ORR of 58.9% (CI: 42.1–74.4). Median duration of response was 6.4 (CI: 5.8–7.0) months and median progression-free survival was 6.0 (CI: 4.3–7.8) months. Three patients (8%) had durable responses lasting  > 12 months. Median overall survival was 8.7 (CI: 7.8–9.6) months. Most common grade 3/4 toxicities were haematological (36%) and renal (21%). Conclusion: Everolimus in combination with cisplatin is an effective first-line treatment option for advanced EP-NEC, especially in highly selected patients. Trial registration: Clinicaltrials.gov, NCT02695459, https://clinicaltrials.gov/ct2/show/NCT02695459 .