Are Neuroendocrine Neoplasms No Longer a Rare Cancer?

backgroundNeuroendocrine neoplasms (NENs) are consistently referred to as a "relatively" rare heterogenous group of "tumours" with variability in their disease course and outcomes. However, there is a lack of consensus on (a) the group membership, that is, a lack of consistency in which "subtypes" of NEN are included in the group; (b) whether they should continue to be seen as a "heterogenous group," or as separate entities; and (c) whether the term and current definitions of "rare" accurately reflects the true patient population and healthcare requirement. SUMMARY: This opinion article explores the concept of rare, as applied to NENs: the significance of a rare cancer label and what this means for awareness, healthcare provision and, tangentially, those diagnosed. It briefly explores rare cancer definitions, including incidence thresholds and interpretation of definition as demonstrated in the variability in what subtypes are included in databanks or registries, and it also asks whether the currently utilised rare cancer definitions reflect an accurate representation of the true disease burden and fully inform disease-appropriate healthcare planning and provision. KEY MESSAGES: The current definition of "rare cancer" based on incidence alone fails to reflect the true disease burden of NENs and is therefore inadequate, to fully inform healthcare policy, planning and provision for this patient population. This requires either a revision in definition or an alteration in how and what decision-makers utilise and include in their deliberations when assessing and planning service provision.