In accordance with the 2018 GLOBOCAN report, colorectal cancer (CRC) occupies the third place in incidence and the second in mortality worldwide. Recent international reports had showed a rise in the prevalence of CRC in the young population. We evaluated the prevalence, clinicopathological and endoscopic characteristics of the CRC population under 50 years at our institution during a 5-year period. From August 2013 to August 2018, the electronic data of the patients under 50 years diagnosed with CRC in the National Cancer Institute at Mexico City were retrospectively reviewed. To be included in the analysis the initial colonoscopy report perform in our endoscopy unit and the histological diagnosis of adenocarcinoma were needed. Patients that had urgent abdominal surgery before colonoscopy were excluded. The following information was obtained: age, gender, family history of CRC, known hereditary syndrome, clinical presentation, time from initial symptoms to diagnosis, tumor location at initial colonoscopy divided by subsites as right colon, left colon and rectum, tumor morphology in accordance with Borrmann classification, pathology result, initial clinical cancer stage, presence and site of metastasis and mortality. The data generated was analyzed using the SPSS v23 program. Continuous variables were described with medians, means and standard deviation. Qualitative variables were described with relative frequencies. The chi-square test was used to study the difference among groups where necessary with a statistical significance of p <0.05. Of the 1,576 patients diagnosed with CRC, 390 (24.7%) were younger than 50 years, 76 were excluded. Among 314 patients,163 (51.9%) were males and 151 (48.1%) females. The median age was 40 (±7.8) years, 49% were between 40-49 years. Seventeen percent had a familiar history of CRC and 14.3% were associated with a hereditary syndrome. Bleeding and abdominal pain were the most common symptoms, with an average delay of 8.8 (± 9.7) months to diagnosis. Main tumor location was the rectum with 59.2% of cases. According to Borrmann class, 68.2% were type III. In 44.3% of cases it was not possible to traverse the tumor. Pathology data showed that 10% of the tumors were grade 1, 55% grade 2, 21.6% grade 3, 3.8% had a mucinous component and 9% had signet ring cell histology. Immunohistochemical mutation analysis showed positive microsatellite instability in 23% of cases. At diagnosis 40% were metastatic. Global mortality was of 47.6%, with a better prognosis in females (37 vs 57.6%) p < 0.001, and right location (27 vs 56%) p < 0.001. (Tables 1-2). A quarter of patients diagnosed with CRC at our institution were younger than 50 years. Majority of cases were sporadic and symptomatic. More than a half of tumors were localized at the rectum and 40% had metastasis at diagnosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)