Abstract 5063: Ancestry-linked, stage-specific delay to tertiary care is associated with survival differences in colorectal cancer

Abstract Background: African-ancestry (AFR) patients with colorectal cancer (CRC) have worse overall survival (OS) than non-AFR patients. While biological and socioeconomic (SES) factors are known to play a role, delayed access to specialized care remains a critical, underexplored driver of this inequity. This study investigates how the time from diagnosis (Dx) to arrival at a tertiary cancer center interacts with ancestry, disease stage, SES, and genomics to affect OS. Methods: We analyzed data from 4,328 CRC patients (259 AFR, 4,069 non-AFR) treated at Memorial Sloan Kettering Cancer Center (MSK) since 2014. Tumors were sequenced with MSK-IMPACT, a targeted DNA sequencing assay that profiles genomic changes in 341-505 genes. Genetic ancestry was inferred from sequencing data with 80% African ancestry fraction grouped as AFR. OncoKB identified clinically actionable genomic alterations. Covariates included tumor location, stage at Dx, time from Dx to MSK arrival (Early ≤90 days vs Late 90 days), insurance type and metastatic burden. OS from Dx was compared using Kaplan-Meier curves and log-rank test, with left-truncation for genomic sequencing date. Results: AFR patients had worse OS from Dx than Non-AFR patients (median 39.3 vs 62.7 months, p0.001). This difference remained when stratified by stage at Dx (Stage I-III: 65.3 vs 96 months, p0.001; Stage IV: 31.6 vs 36.7 months, p=0.03). AFR patients also had significantly longer delays from Dx to arrival (median: 22 IQR: 10, 173 vs 14 IQR: 6, 38 days; p0.001) and a higher proportion of late arrivals (28.7 vs 17.1%, p0.001). This difference was more evident in Stage I-III (49.6 vs 25.9%, p0.001) than in Stage IV (6.3 vs 5.6%, p=0.69). There was no significant difference in OS between AFR and Non-AFR for Stage I-III early (median: Not Reached (NR) vs NR, p=0.98), Stage I-III late (median: 36 vs 43.5 months, p=0.24), and Stage IV late (median:43.7 vs 33.9 months, p=0.48) arrival, but was significant in Stage IV early arrival (median: 31.6 vs 36.9 months, p=0.034). Patients diagnosed with Stage I-III disease who arrived late at MSK were often Stage IV at their time of arrival (AFR: 68.9%, Non-AFR 65.8%) but this was much less frequent among early arrivals (AFR: 6.1%, Non-AFR: 2.6%); and was linked to higher Medicaid use in both AFR (10.8% vs 1.5%; p=0.03) and Non-AFR (4.4% vs 2.4%; p=0.015) patients. AFR had higher KRAS mutation frequency compared to Non-AFR across all stages and arrival groups (Stage I-III Early: 51.5 vs 38.8%, p=0.04; Stage I-III Late: 58.2 vs 47.2%, p=0.10; Stage IV Early: 58.5 vs 44.5%, p=0.004; Stage IV Late: 75 vs 50.5%, p=0.28). Conclusion: Delayed specialized care appears to be linked to CRC survival gaps in AFR patients, especially in the non-metastatic setting where timely multidisciplinary care is crucial. Expediting referral of AFR patients to tertiary care centers could help to achieve CRC outcome equity. Citation Format: Sharafudeen Dahiru Abubakar, Henry Walch, Christina Lee, David Gomez Sanchez, Chin-Tung Chen, Stefanie Gerstberger, Kanika Arora, Farheen Shah, Tejiri E. Agbamu, Michele Waters, Christopher J. Fong, Justin Jee, Michael F. Berger, Karuna Ganesh, Debyani Chakravarty, Walid Khaled Chatila, Nikolaus Schultz, Rona Yaeger, Julio Garcia-Aguilar, Francisco Sanchez-Vega, . Ancestry-linked, stage-specific delay to tertiary care is associated with survival differences in colorectal cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5063.