Clinical-pathologic characteristics in young patients with metastatic colorectal cancer: Experience from a specialized cancer institute in Peru.

279 Background: Colorectal cancer (CRC) represents the third cause of malignant neoplasm in the world and the second in terms of mortality. CRC is a major cause of cancer-related morbidity and mortality in Peru. Diagnosis at younger ages represents a challenge. In this study, we evaluated prognostic factors in patients who were metastatic at diagnosis or progressed to metastatic disease during follow-up. Methods: A descriptive cross-sectional study, between 2013 and 2022, 66 patients under 40 years old and stage IV at diagnosis were analyzed. Parameters evaluated were age, gender, comorbidity, performance status and stage of the disease at the diagnosis, localization, surgery undergone, systemic treatment regimen, response to first-line treatment, incidence of K-RAS, sites and number of metastases, expression of tumor predictors (CEA levels), and survival times. A multivariate analysis was conducted with factors that were considered statistically significant in the univariate analysis. Results: Median age was 35 years [29.25-37] and the female/male ratio was 34/32. From 66 patients at stage IV disease, 30 patients (45.5%) were right-side, 36 (54.5%) were left-side colon cancer. At the end of follow-up, 51 patients had died, and 15 survived. Overall survival (OS) was significantly better in patients older than 35 years old (p<0,05), those who underwent primary tumor surgery (p<0,001), negative perineural invasion (p<0.0045). The treatment most common was CAPOX with a median OS of 17 months (p<0.013). The multivariate analysis shows that patients who did not undergo primary surgery had worse disease-specific OS (hazard ratio, CI 2.21.95% [1.15-4.25], p< 0.018) and there was no statistical difference between chemotherapy regimens and treatment line. Conclusions: In young patients with metastatic CRC, Primary tumor surgery and negative perineural invasion are significant factors influencing overall survival. Patients older than 35 years and those who underwent surgery showed better survival. These findings reflect the importance of early colorectal cancer screening and improve the risk assessment.