DOI: 10.4274/tjcd.galenos.2021.2021-3-1 Turk J Colorectal Dis RESEARCH ARTICLE Early Onset Colorectal Cancer: Younger Patients, More Advanced Stage and Worse Postoperative Results: A Retrospective Review Avellaneda Nicolás 1 , Lasa Juan 2 , Olivera Pablo 2 , Hernández Agustín 1 , Veracierto Federico 1 , Santillán Mateo 1 , Oddi Ricardo 1 , Carrie Augusto 1 1 General Surgery Department, Centre for Medical Education and Clinical Investigations “Norberto Quirno” (CEMIC). Galván 4102 , C 1431 CABA, Argentina 2 Gastroenterology Department, Centre for Medical Education and Clinical Investigations “Norberto Quirno” (CEMIC). Galván 4102 , C 1431 CABA, Argentina ABSTRACT Aim: The incidence of colorectal tumors in young patients has been rising lately, and current investigations are directed to determine causes and prognosis of this type of patients. The objective of this publication is to analyze results of surgical treatment and tumor stages in young patients, and compare them to those in older individuals. Method: A retrospective analysis of patients undergoing surgery for colorectal adenocarcinoma during 2015-2020 in a single institution was performed, dividing them into two categories: those younger than 50 years old, early onset colorectal cancer (EOCRC), and those on age for colorectal cancer screening, average onset colorectal cancer (AOCRC), focusing on disease stage and postoperative outcomes. Results: Two hundred and seven patients were included, thirty-two in the EOCRC group. Median age was 42.10 years (SD= 5.74) and 65.38 years (SD= 7.19) respectively, dyslipidemia was more prevalent in AOCRC patients. EOCRC patients had more upper rectum (28.13 vs. 8%, p= 0,001) and transverse colon (21.88 vs. 10.29%, p=0.06) tumors, had higher rates of complications (43.75 vs. 28%, p=0.07) and reoperations (18.75 vs. 7.43%, p=0.04). Moreover, major complications were more frequent in younger patients. EOCRC had significantly more stage IV tumors (18.75 vs. 5.13 %, p=0,01), and 46.86% of these individuals had an advanced disease at the time of surgery. Conclusion: EOCRC is diagnosed at more advanced stages of the disease and presents differences in tumor location. Complications including need of reoperation are more frequent in this group. Keywords: Colorectal adenocarcinoma, early onset, screening strategies, colonoscopy, advanced stage Address for Correspondence/Yazışma Adresi: Nicolas Avellaneda, General Surgery Department, Centre for Medical Education and Clinical Investigations “Norberto Quirno” (CEMIC). Galván 4102, C1431 CABA, Argentina E-mail: n.avellaneda86@gmail.com Received/Geliş Tarihi: 07.03.2021 Accepted/Kabul Tarihi: 04.05.2021 Introduction Colorectal cancer (CRC) is the third cancer in incidence in both males and females worldwide, only outnumbered by breast and lung tumors. It is also the second cause of cancer related deaths [1]. Significant advances have been made in early diagnosis of CRC due to the development of population screening strategies performing exams which detect potentially neoplastic polyps at an early stage [2]. The most widely-used screening procedure is colonoscopy, and an association has been found between its implementation and a significant reduction in CRC incidence [3, 4]. According to current guidelines, the indication for screening colonoscopy is recommended for patients between 50-75 years old [5], average-onset of CRC (AOCRC). On the other hand, there is a rising concern due to the increase in CRC among younger patients, a trend that has been formerly addressed as “Early Onset CRC” (EOCRC) [6]. Screening in patients from 45 to 49 years old is being considered as a Grade B recommendation by the US Preventive Service Task Force, although no definitive recommendation has been published since 2016. Early diagnosis and treatment of these patients remain challenging, as they are not included in screening strategies, and consequently, they may consult at an advanced stage, usually when they are overtly symptomatic. It has been