Colorectal cancer in young Tunisian patients: clinical, histopathological and RAS testing data

Abstract

Introduction: Colorectal cancer (CRC) is the third most common malignancy and the second leading cause of cancer-related deaths worldwide. Approximately 5%of cases arise in patients under the age of 45 years. In this group, only a minority could be related to inherited syndromes with specific pathogenesis and well-characterized data. Knowledge regarding the molecular features of sporadic CRC in young patients is limited. The aim of this study is to assess the histopathological epidemiological and RAS mutation data in young-onset CRC Methods: 1503 Formalin fixed paraffin embedded samples of CRC were analyzed. Data on gender, localization, stage, and histological characteristics were collected from histopathological reports then compared between patients aged under and over 45 years. RAS mutation status was performed using Lightmix kit (TibMolBiol). Statistic analysis was performed by SPSS 13 Results: Of 1503 patients, 17.4% were under 45 years. In this group, 50.6% were females with a tumor localized predominantly in the left bowel (40.6%) followed by the rectum in 36.7% of cases. 50.3% of tumors were in stage III with a high lymph node involvement (69.9%). The most common histopathological type was moderately differentiated adenocarcinoma (79.7%) but there was a high proportion of signet ring cell carcinomas (5.7%) and poorly differentiated carcinomas (5%). The RAS status showed a mutation in 44.6% of cases. Comparison between patients under and over 45 years showed a significant difference only in gender and histological type distribution. Conclusion(s): The proportion of young-onset CRC (<45 years) in Tunisian patient is higher than those reported previously in the literature. This could be related to the high proportion of consanguinity in Tunisia. Compared with late onset CRC, young-onset CRC occurs more frequently in females and have a high proportion of signet ring cell and poorly differentiated carcinomas. These characteristics could have implications in the prevention, diagnosis, and management of these individuals.