Prevalence and Clinical Characteristics Associated with KRAS Gene Mutations in Colorectal Cancer in Ecuadorian Patients: A Cross-Sectional Study.

Introduction: Colorectal cancer is recognized as the third most common malignant neoplasm worldwide. In Ecuador, it ranks fourth in incidence and third in mortality. The KRAS gene mutation has been associated with a poorer prognosis due to its contribution to resistance against anti-EGFR monoclonal antibody therapies. The aim of this study was to determine the prevalence and clinical characteristics associated with the KRAS gene mutation in Ecuadorian patients with colorectal cancer. Methods: A retrospective cross-sectional study was conducted, including patients diagnosed with colorectal cancer between 2018 and 2022 at a specialized cancer center, and the KRAS gene mutation status was evaluated. The relationship between KRAS mutation status and clinicopathological characteristics was analyzed. Results: A total of 152 patients were included in the study. Of these, 52% were women, with a mean age of 62.01 years, and 78.3% were over 50 years old. The prevalence of the KRAS mutation was found to be 44.7%. The most frequent cancer stage was IV A (18.4%), and the majority of primary tumors were located in the rectum (34.9%). An association between KRAS mutation status and the location of the primary tumor was identified (p=0.030). However, no association was observed between mutation status and other sociodemographic or clinical variables. Conclusion: Approximately 4 out of 10 Ecuadorian patients with colorectal cancer were found to have the KRAS gene mutation. This mutation was associated with tumor location, particularly in the descending colon. However, no associations were identified with other sociodemographic or clinical variables.