Prognosis of NETs: Has There Been Improvement over the Last 30 Years?

Neuroendocrine tumours (NETs) are uncommon tumours, initially described as "Carzinoides" over hundred years ago and had since then multiple changes in terminology and difference in consideration of benign or malignant tumours. There have been multiple subclassifications and definitions made by the World Health Organisation (WHO). Multiple studies suggest an increase in incidence and prevalence. There are three types of sources of information for these studies; national databases, regional databases or single-centre studies. These different sources of data describe small or larger cohorts of patients with NETs, including risks of bias and concerns regarding accuracy of data. The studies aim to describe the prognosis of patients with NETs, using outcomes as overall survival (OS), progression-free survival and relative survival rate. There is a heterogeneity of studies including different patient populations, different study periods, different definitions, and different outcomes of prognosis it is difficult to compare studies.This review aims to describe how the prognosis changed in the past 30 years for patients with NETs taken into account changes in treatment. During the past 3 decades, new treatments including targeting somatostatin receptors with somatostatin analogues or peptide receptor radionucleide therapy, systemic anti-cancer treatments with Sunitinib, Everolimus, and Cabozantinib were developed. In this review, the treatments and prognosis between 1990 and 2000 are described. Subsequently per decade 2000-2010, 2010-2020, and 2020-currently, new treatments and up to date studies regarding the prognosis are reviewed. The aim of this study was to explain changes in prognosis of patients with NETs.