Unique Metastatic Patterns in Neuroendocrine Neoplasms of Different Primary Origin

Introduction: Neuroendocrine neoplasms (NEN) can originate in different organs, for example, the gastroenteral tract (GE), pancreas (Pan), or lungs (L). Our aim was to examine metastatic patterns for patients with NEN of various primary origins with a special focus on brain metastases to indicate utility for screening.   Methods: All NEN patients except for small cell lung cancer registered in the Netherlands Cancer Registry from 2008 to 2018 were selected. Metastatic patterns at initial diagnosis for NEN with different primary origins were compared. In a subcohort of patients from 2 referral hospitals (2014-2019), additional information on, for example, development of metastases after initial presentation was available.   Results: In the nationwide cohort, 4,768/11,120 (43%) patients had metastatic disease at diagnosis (GE: 1,504/4,710 [32%]; Pan: 489/1,150 [43%]; and L: 1,230/2,978 [41%]). For GE- and Pan-NEN, the most prevalent metastatic site was the liver (25 and 39%), followed by distant lymph nodes (8 and 8%), whereas only few patients with brain metastases were identified (0% in both). In contrast, for L-NEN, prevalence of metastases in the liver (19%), brain (9%), lung (7%), and bone (14%) was more equal. In the reference network cohort, slightly more NEN patients had metastatic disease (260/539, 48%) and similar metastatic patterns were observed.   Conclusion: Almost half of NEN patients were diagnosed with synchronous metastatic disease. L-NEN have a unique metastatic pattern compared to GE- and Pan-NEN. Remarkably, an important part of L-NEN metastases was in the brain, whereas brain metastases were almost absent in GE- and Pan-NEN, indicating utility of screening in L-NEN

Clinical-Pathologic Challenges in the Classification of Pulmonary Neuroendocrine Neoplasms and Targets on the Horizon for Future Clinical Practice

Diagnosing a pulmonary neuroendocrine neoplasm (NEN) may be difficult, challenging clinical decision making. In this review, the following key clinical and pathologic issues and informative molecular markers are being discussed: (1) What is the preferred outcome parameter for curatively resected low-grade NENs (carcinoid), for example, overall survival or recurrence-free interval? (2) Does the WHO classification combined with a Ki-67 proliferation index and molecular markers, such as OTP and CD44, offer improved prognostication in low-grade NENs? (3) What is the value of a typical versus atypical carcinoid diagnosis on a biopsy specimen in local and metastatic disease? Diagnosis is difficult in biopsy specimens and recent observations of an increased mitotic rate in metastatic carcinoid from typical to atypical and high-grade NEN can further complicate diagnosis. (4) What is the (ir)relevance of morphologically separating large cell neuroendocrine carcinoma (LCNEC) SCLC and the value of molecular markers (RB1 gene and pRb protein or transcription factors NEUROD1, ASCL1, POU2F3, or YAP1 [NAPY]) to predict systemic treatment outcome? (5) Are additional diagnostic criteria required to accurately separate LCNEC from NSCLC in biopsy specimens? Neuroendocrine morphology can be absent owing to limited sample size leading to missed LCNEC diagnoses. Evaluation of genomic studies on LCNEC and marker studies have identified that a combination of napsin A and neuroendocrine markers could be helpful. Hence, to improve clinical practice, we should consider to adjust our NEN classification incorporating prognostic and predictive markers applicable on biopsy specimens to inform a treatment outcome-driven classification.</p

Long-term survival in patients with gastroenteropancreatic neuroendocrine neoplasms: A population-based study

Background: Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) comprise a group of rare malignant tumours with heterogeneous behaviour. This study aimed to assess long-term survival and prognostic factors associated with survival, in order to optimise counselling. Patients and methods: This population-based study included all GEP-NENs diagnosed between 1989 and 2016 in the Netherlands, selected from the Netherlands Cancer Registry. Overall survival (OS) and relative survival (RS) were calculated. A Cox Proportional Hazard analysis was used to identify prognostic factors (gender, age, tumour stage, location and treatment) for OS. Analyses were stratified by metastatic disease status and tumour grade. Results: In total, 9697 patients were included. In grade 1, 2 and 3 non-metastatic GEP-NENs (N = 6544), 5-year OS and RS were 81% and 88%, 78% and 83%, and 26% and 30%, respectively. In grade 1 non-metastatic GEP-NENs 10-year OS and RS were 68% and 83%. In grade 1, 2 and 3 metastatic GEP-NENs (N = 3153), 5-year OS and RS rates were 47% and 52%, 38% and 41%, and 5% and 5%, respectively. The highest (relative) survival rates were found in appendicular and rectal NENs, demonstrating 10-year OS and RS of 87% and 93%, and 81% and 95%, respectively. Conclusions: These long-term follow-up data demonstrate significant differences in survival for different grades, tumour stage, and primary origin of GEP-NENs, with the most favourable overall and RS rates in patients with non-metastatic grade 1 appendicular and rectal NENs. This study demonstrates unique long-term OS and RS rates using combined stratification by tumour site, grade and stage