199 Clinical and Molecular Characteristics of Early-Onset Colorectal Cancer Across Various Ethnicities

Abstract

INTRODUCTION: Colorectal cancer (CRC) is the third most common cancer in the United States. Guidelines from the American Cancer Society recommend CRC screening at 45 years of age in average-risk patient populations. Previous studies have shown an increase in incidence of CRC in African Americans (AAs) less than 50 years of age. We aimed to examine the disease characteristics of patients with early-onset CRC (EOCRC) across different races. METHODS: A retrospective cross-sectional study was performed using our electronic pathology database. All patients diagnosed with CRC between January 2012 and September 2018 were included. Data regarding patient demographics, co-morbid conditions and patient presentation was noted. In addition to information regarding the location, staging and molecular features of CRC. RESULTS: A total of 627 patients with CRC were identified. Out of these, 117 (18.6%) were younger than 50 years of age (EOCRC). Table 1 compares the baseline characteristics of patients across different races. The mean age of onset of CRC was significantly lower in Hispanics compared to Caucasians [56.6 years vs 61.6 years, P value = 0.0002] and AAs [56.6 years vs 60.2 years, P value = 0.01]. The clinical and molecular features of CRC across different racial groups are summarized in Table 2. The proportion of patients with early-onset CRC was higher in Hispanics as compared to Caucasians (27.9% vs 16.0%, P value = 0.004) and AAs (27.9% vs 16.9%, P = 0.03). On a multivariate analysis after adjusting for confounders, the proportion of Hispanics with early-onset CRC was significantly higher as compared to Caucasians [OR: 2.2, (95% CI 1.3–3.7), P value = 0.003]. Hispanics were less likely to harbor BRAF mutation as compared to Caucasians (5.1% vs 13.1%, P-value: 0.05), while Hispanics were more likely to have mutations in MSH-6 (100% vs 91.3%, P-value: 0.01) and MSH-2 (100% vs 94.2%, P-value = 0.05) as compared to AAs. CONCLUSION: Our study shows that proportion of patients with early-onset CRC is higher in Hispanics as compared to Caucasians and AAs. In addition, there are unique molecular features specific to CRC across various racial groups. Our findings raise concerns that there might be knowledge gaps regarding early-onset CRC amongst minority populations. Further large multi-center studies are needed to better understand the unique clinical and molecular characteristics in early-onset CRC in minority populations.