Clinical presentation and outcomes of sporadic neuroendocrine neoplasms in young adults

Most neuroendocrine neoplasms (NENs) are sporadic and occur predominantly in older patients. Early-age disease onset has been increasingly observed in NENs. We aimed to assess the clinical features and outcomes of young adults with sporadic NENs.

This is a retrospective study that gathered 20 institutions from 12 countries under the auspices of Women in NET (WiN) ENETS group.

Young patients aged 18-40 years diagnosed with sporadic NENs (well and poorly differentiated) from 2010 to 2020 were enrolled. Patients with appendiceal and type 1 gastric NETs, hereditary syndromes, synchronous malignancy, pheochromocytoma, paraganglioma, and medullary thyroid cancer were excluded. Descriptive statistics, comparisons between groups, survival, and Cox multivariable analysis were performed.

Overall, 478 young patients with sporadic NENs were enrolled. Localised (62%, n = 249), well-differentiated (92%, n = 433), non-functioning tumours (81%, n = 384), and women (58%, n = 277) were more prevalent. The pancreas was the most common primary site (33%, n = 159). Metastatic disease at diagnosis was more often found in men than women (47%, n = 78 vs. 33%, n = 78, P = .004). Five-year overall survival was 82%. Overall survival was significantly longer in women than men (P = .019), as well as in rectal (P = .00245) and lung (P = .0027) primary tumours compared to pancreatic NENs. The multivariable analysis identified stage, Ki-67, morphology, and gender as independent predictors of survival.

Young patients with NENs often present with well-differentiated and localised tumours, thereby increasing the probability of curative surgical resection. Prospective research into molecular biology is needed to identify distinct NEN features in young adults and determine risk factors to tailor effective treatment strategies.