[Early-onset Colorectal Cancer: Epidemiological and Clinical Characteristics and Survival Analysis in a Hospital Cohort].

Introduction: Colorectal cancer in adults under 50 years of age, known as early-onset colorectal cancer, has shown a progressive increase in incidence worldwide. This age group is usually excluded from screening programs. Objectives: To describe the epidemiological and clinical characteristics and survival outcomes of patients with early-onset colorectal cancer treated at a referral center. Materials and methods: A retrospective cohort study that included patients up to 49 years of age with a histological diagnosis of colorectal adenocarcinoma treated between 2015 and 2024. Clinical variables, tumor location, TNM stage, and survival were analyzed. Results: A total of 56 patients were included, with a median age of 42 years (IQR 13.3). The most frequent tumor location was the right colon (32.1%). Fifty-seven percent had advanced-stage disease and 33.9% had metastases at diagnosis. The median overall survival was 78 months, with a 5-year survival rate of 59.3%. The presence of metastases at diagnosis was independently associated with poorer survival (HR 2.38; 95% CI 1.08 - 5.26; p = 0.031), and age under 40 years showed a trend toward poorer prognosis (HR 2.17; 95% CI 0.95-5.00; p = 0.065). Conclusion: Although the right colon was the most common individual site, no clear predominance of any tumor site was observed. The cohort was characterized by a high proportion of advanced disease at diagnosis and an overall survival rate lower than that reported in other series. Metastatic disease was the main determinant of survival, and patients younger than 40 years of age tended to have a poorer prognosis.