Early-Onset colorectal Cancer: From the laboratory to the clinic

Highlights•By 2030, almost one quarter of rectal cancers will occur in people < 50 years.•Inheritance is responsible for 25 % of cases < 50 years and 33 % of cases < 35 years.•EOCRC often have left-sided/rectal tumors and are diagnosed in advanced stages.•EOCRC are more dMMR/MSI, BRAF wild type and mutated in inheritance-related genes.•It is still uncertain if they have a distinct biology with a distinct prognosis.AbstractColorectal cancer that occurs before age of 50 is defined as Early-Onset Colorectal Cancer (EOCRC). Its incidence has worryingly increased since the late 90 s and is expected to keep rising in the next future, despite Late-Onset CRC (LOCRC) is decreasing worldwide. Because of this, there is an urgent need to better understand this subset of patients in order to give them the best treatment possible. However, most of the literature is retrospective and often discordant. In this review, we aim to provide a general overview of the issue, endeavoring to highlight the current available knowledge. We decided to move from the beginning, investigating risk factors and inheritance, passing through diagnosis and clinical aspects, and to conclude with the translational part, focusing on the biology of the tumor. However, lot of questions remain open, including screening age and prognosis. Indeed, young patients tend to be treated more aggressively, even if a survival benefit has not been proven yet. Every clinician should be aware of the best practice for young people, and more translational studies are awaited in order to clarify is EOCRC represents a distinct biological entity.