Simple SummaryEarly-onset colorectal cancer is increasing in incidence in the United States, and it is expected to more than double in the next 10 years. There are many risk factors that lead to the development of early-onset colorectal cancer, including hereditary cancer syndromes, such as Lynch syndrome, obesity, diet, sedentary lifestyle, inflammatory bowel disease and altered microbiome. There is a significant lack of awareness of early-onset colorectal cancer, and the rise in the number of cases indicates that more coordinated efforts are needed to understand and treat early-onset colorectal cancer better, through promoting the benefits of screening, including genetic profiling, and increasing adherence to current screening guidelines. The aim of this review is to discuss the available literature regarding early-onset colorectal cancer to better define the risk factors, histopathology, genetic makeup and management.AbstractOver the past decade, the incidence of colorectal cancer has increased in individuals under the age of 50 years. Meanwhile, the incidence has gradually decreased in the older population. As described herein, we reviewed the available literature to summarize the current landscape of early-onset colorectal cancer, including risk factors, clinicopathological presentation, genetic makeup of patients, and management. Currently, early-onset colorectal cancer is treated similarly as late-onset colorectal cancer, yet the available literature shows that early-onset colorectal cancer is more aggressive and different, and this remains a significant unmet need. A detailed understanding of early-onset colorectal cancer is needed to identify risk factors for the increased incidence and tailor treatments accordingly.