Colorectal Cancer Screening in Araba (Basque Country)

Abstract

Background and objectives: Colorectal cancer (CRC) ranks third in incidence and second in mortality worldwide. In Ecuador, there are 2,481 new CRC cases per year and 2,366 cancer deaths yearly. CRC presents in stages III-IV in more than 50% of patients. The standard treatment for CRC is chemotherapy, with an overall survival (OS) of 29-31 months. The status of biomarkers KRAS, NRAS, BRAF, and MSI provides prognostic and predictive value. This study aimed to determine OS and progression-free survival (PFS) for metastatic CRC based on these molecular markers with a minimum follow-up of one year. Methods:This was an observational longitudinal analytical study at the Hospital de Especialidades Eugenio Espejo (HEEE). We obtained demographic, anatomopathological-molecular, and clinical data from the medical records of patients with metastatic CRC from July 1, 2018 until December 31, 2020.Results: Data were collected from a total of 177 patients. The median follow-up was 21.6 months. The median PFS was 15 months (11.6-18.3) in those with mutated (MT) markers, 18 months (15.7-20.2) for wild type (WT), and 9 months (4.1-13.8) for not performed markers (NR), with a hazard ratio (HR) for PFS in MT versus WT of 0.76; the 95% confidence interval (CI) (0.4-1.4) with p = 0.4. for OS was 21 months (17.1-24.8) for MT markers,[22][23][24][25][26]2) for WT markers, and 19 months (17.7-20.2) for NR. There were no significant differences in OS for MT vs. WT: HR = 1.38, 95% CI (0.8-2.3) p = 0.6. There was no significant association between OS or PSF and KRAS, NRAS, BRAF, and MSI mutations. KRAS was the most mutated marker, with a frequency of 40.2%. Conclusions:In the first monocentric study of mutations in metastatic CRC patients from Ecuador, patients with WT molecular markers reached the most prolonged OS and PFS, and KRAS had the highest mutation frequency. However, further studies with larger sample sizes are required to corroborate our findings.