EARLY-ONSET COLORECTAL CANCER: AN ELEVEN-YEAR ANALYSIS OF CLINICOPATHOLOGICAL CHARACTERISTICS AT A TERTIARY HEALTHCARE CENTER.

•The incidence of early-onset colorectal cancer (EO-CRC) has significantly increased worldwide, often leading to advanced disease at the time of diagnosis. •This study investigates the clinicopathological characteristics of EO-CRC cases at an academic healthcare center in Spain. •The majority of patients with EO-CRC were diagnosed between 40-49 years of age. •Left-sided tumors were more common, and most patients were diagnosed at advanced stages. •Moderately differentiated adenocarcinoma was the most frequent histological type, with 18.8% showing KRAS mutation and 11.9% showing BRAF mutation. Background - Early-onset colorectal cancer (EO-CRC) incidence has increased significantly worldwide in recent years, and these individuals frequently have advanced disease at the time of diagnosis. This study examines the clinicopathological characteristics of EO-CRC cases diagnosed at an academic healthcare center in Spain. Methods - A retrospective record review study of patients diagnosed with EO-CRC from 2010 to 2021 was performed. Clinical and pathological data were collected. Results - A total of 101 patients were included. The majority of cases (75.3%) were diagnosed in the age group between 40 and 49 years, specifically within the subgroup of 46-49 years. A family history of colorectal cancer was found in 23% of patients. Left-sided tumors were more common (43.6%), and most patients were diagnosed at advanced stages (34.7% at stage III and 32.7% at stage IV). The majority of patients (94.1%) were symptomatic, with rectal bleeding being the most prevalent clinical presentation. The most frequent histological type was moderately differentiated adenocarcinoma (44.6%). KRAS mutant tumors were found in 18.8% and BRAF mutant tumors in 11.9%. 67.3% had microsatellite stability. Tumor recurrence occurred in 24.8% of the patients, while 27.7% of the patients died. Conclusion - From 2010 to 2021, EO-CRC accounted for 3% of all colorectal cancer cases. To improve early diagnosis and treatment, physicians should maintain a high suspicion of red flag symptoms in young patients. To decrease EO-CRC morbidity and mortality, starting diagnostic screening tests at age 45 should be considered.