Racial differences in genomic profiles and clinical outcomes of patients with colorectal carcinoma: A single institution retrospective study.

Abstract

e15582 Background: In the era of precision oncology, there is an immediate need to study the heterogeneity of molecular biology and clinical outcomes in racially diverse colorectal cancer (CRC) patients. Black patients are known to have poorer outcomes compared to their white counterparts. Understanding differences in patients’ molecular and genomic profiles may help explain these racial disparities. Methods: Demographic and clinical outcome data was abstracted from medical records of colorectal cancer patients who were diagnosed between 2008 and 2021 at The University of South Alabama. Tumor only next generation sequencing (NGS) of DNA (592 or WES) and RNA (WTS) was performed at Caris Life Sciences (Phoenix, AZ). Overall survival (OS) was defined as time from diagnosis to death or last contact. Descriptive analyses were performed using t-test and chi-square test, survival analyses were performed using Kaplan-Meier method and Log rank test (GraphPad Prism version 10.1.1). Results: 66 patients with CRC were included, 73% were white and 27% were black. The median age for white patients was 60.5 years and for black patients was 55.5 years (p = 0.049). In the white population, 52.1% of the patients were male and 47.9% were female. In the black population, 33.3% were male and 66.7% were female. The most common sites of malignancy for white patients were rectum (32.6%) and sigmoid (26.1%), whereas for black patients the most common sites were sigmoid (27.8%) and cecum (22.2%). Overall, the most common mutations were TP53 (68.2%), APC (65.2%), KRAS (47%), SMAD4 (16.7%), and FBXW7 (13.6%). The prevalence rates of TP53 (77.8 vs 64.6%), APC (72.2 vs 62.5%), KRAS (66.7 vs 39.6%), and SMAD4 (27.8 vs 14.6%) trended higher in black patients, with KRAS being statistically significant (p = 0.049). FBXW7 trended higher in white patients (14.6 vs 11.1%). Eleven (23%) white patients had a variant of uncertain significance in the ATM gene, which was not observed in black patients. More white patients had stage IV disease compared to black patients (69% vs 50%). No statistically significant difference in OS was found between races (HR 0.68, 95% CI of 0.35 to 1.3, p = 0.2). However, white patients had a median OS of 1334 days compared to 927 days for black patients. Conclusions: White and black CRC patients have unique molecular tumor profiles that may better explain the differences in survival. Our results warrant larger studies with racially and ethnically diverse patient populations to explore these racial disparities and close the gap in colorectal cancer care.