Comparison of universal germline sequencing in White vs. minority populations with primary gastrointestinal malignancies.

Abstract

817 Background: Universal germline sequencing is increasingly utilized in practice, but existing evidence and guidelines are based on studies in predominantly white populations. This study aims to compare the prevalence of genetic alterations in white vs underrepresented minority (URM) populations and assess incremental findings discovered with universal testing beyond current guidelines. Methods: This prospective, multicenter study analyzed genetic alterations in white and URM cohorts with primary GI malignancies receiving care at Mayo Clinic cancer centers between April 2018 and April 2025. Patients underwent germline sequencing using a next-generation sequencing (NGS) platform targeting over 80 genes. We compared the distribution of results between white and URM populations. Concordance with NCCN testing guidelines and incremental findings were assessed. Results: A total of 1128 patients were studied, of which 758 were white and 370 were URM, (47.6% Hispanic, 22.7% Black, 13.8% Asian, 10.5% American Indian, 0.8% Pacific Islander, and 6.8% other). Pathogenic variants (PGV) were more common in the white population (16.1% vs 9.2% P < 0.001). Variants of uncertain significance (VUS) were more common in the URM population (53.2 vs 43.5%, P<0.001). A total of 156 patients were found to have a PGV. PGVs outside primary cancer genes were more common in white patients (57.4% vs. 32.4%; p=0.0241). Incremental findings from universal testing were higher in white patients (66.4% vs 35.3%; p=0.0011). Conclusions: This study reveals a significant difference in the prevalence of PGV and VUS between white and URM patients with primary GI malignancies. The higher rate of PGVs in white patients and VUS in URM patients highlights potential inequities in both detection and interpretation of genetic results. These findings emphasize the need for broader representation in genetic databases to ensure equitable access to precision oncology. Screening guidelines met by patients with PGV. White (N=122) URM (N=34) Total (N=156) p value Did they meet NCCN testing guidelines for their primary cancer? 0.0991    Yes 87 (71.3%) 29 (85.3%) 116 (74.4%)    No 35 (28.7%) 5 (14.7%) 40 (25.6%) Was the PGV outside of the primary genes recommended for their primary cancer? 0.0241    Yes 70 (57.4%) 11 (32.4%) 81 (51.9%)    No 47 (38.5%) 22 (64.7%) 69 (44.2%) Incremental Finding 0.0011    Yes 81 (66.4%) 12 (35.3%) 93 (59.6%)    No 41 (33.6%) 22 (64.7%) 63 (40.4%)