Gastric cancer (GC) is a major health problem worldwide, ranking the 6th place in incidence with new 30000 cases expected in the next decades [1]. Although GC is not a big killer, however, it has high mortality rates, ranking the 5th place in the tumour-related death list [1]. This fact is also due to a late diagnosis, especially in Western countries, where no screening programs are active. Thus, the tumour is often diagnosed as advanced or metastatic disease with a median overall survival (OS) of 10–12 months. Additionally, even in the case of non-metastatic tumour, the rate of relapses after curative surgery is high [2], leading to a poor outcome.

In this context, the occurrence of GC in the young population depicts an even worse scenario. In fact, if GC has historically arisen mainly in man with a median age of 65 years at the diagnosis, during the last decades an increased trend for the appearance of early-onset GC has been reported [3, 4, 5]. Early-onset GC could be diagnosed as part of a genetic syndrome, such as the hereditary diffuse GC [6] or the Lynch ones, for example. However, hereditary early-onset GC can account for only 3% of all GC in young adult, whereas the majority of the cases are sporadic. Then, the diagnosis of GC in a young adult population along with the low survival rates are a major challenge from both individual (physical and psychological) and social point of views. However, considering that the early-onset forms were less frequent in the past, the increasing number in the last decades has improved the interest and awareness of them in the society and in the scientific community. In particular, the different behaviour and characteristics of GC in those patients seems to suggest that it is a completely different clinical entity, which requires a tailored and personalized management.

Based on this background, the aim of this narrative review is to provide an updated overview about non-hereditary early-onset GC, which is an unmet clinical need today, along with future perspectives in this field. Therefore, the discussion about early-onset GC with hereditary etiology will be not in the aim of this review.