Abstract
Neuroendocrine neoplasms, though rare, have shown marked increases in global incidence and prevalence over the past decade, as demonstrated by cancer registry data and studies from specialised tertiary centres. However, it remains unclear whether this represents a true increase in incidence or enhanced detection capabilities across various countries. This review aims to analyse and discuss recently published data on the worldwide epidemiology of gastroenteropancreatic NEN, and bronchopulmonary NEN and explore potential trends and differences in incidence rates between large and small nations according to demographics, primary sites, grade and stage. Following PRISMA guidelines, 59 cohort studies published between 2014 and 2024 were analysed. Findings reveal mixed demographic patterns, with a slight male predominance in overall NEN incidence but site-specific variations influenced by genetic, hormonal, and environmental factors. Median age at diagnosis is 60 years, though appendiceal NENs typically affect younger individuals. Racial disparities were noted, with higher incidence rates among Black populations in the USA, though findings varied across studies. Globally, the incidence of NENs has increased, with the most notable surge reported in the USA between 1973 and 2012. Similar upward trends were observed in Europe, Asia, and Australia, though to different extents. However, variations in data collection methods present significant challenges for cross-national comparisons. The review highlights the need for standardised methodologies and further research to address gaps in understanding NEN epidemiology in smaller nations and underrepresented regions.