Comparative Analysis of Potential Clinical Actionability of Genomic Alterations in Early-Onset Versus Later-Onset GI...

As biomarker-directed therapy increasingly shapes GI oncology, it remains unclear whether early-onset (EO) and later-onset (LO) GI cancers harbor comparable opportunities for clinically actionable targeting. We compared the landscape of potentially actionable genomic alterations in EO versus LO GI cancers using American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange v19.0.

GI tumor samples were assigned to 10 prespecified tumor groups using OncoTree codes. Samples were annotated with OncoKB therapeutic levels and classified as potentially actionable if they harbored at least one level 1-3B alteration. EO and LO disease were defined as age at sequencing <50 years and ≥50 years, respectively. Group-wise comparisons used Wilcoxon rank-sum, chi-square, or Fisher exact testing as appropriate and with false discovery rate correction. Multivariable logistic regression evaluated age group associations overall and within tumor groups.

Among 53,945 GI tumor samples, 10,573 (19.6%) were EO and 43,372 (80.4%) were LO. EO tumors had lower prevalence of potentially actionable alterations in colorectal (71% v 78.1%, q < 0.001), esophagogastric (53.3% v 57.9%, q = 0.0097), GI stromal tumor (GIST) (75.1% v 90.9%, q < 0.001), liver (25.4% v 35.4%, q = 0.0021), and pancreatic tumors (82.9% v 90.7%, q < 0.001). In the overall model, LO status was associated with higher odds of potential actionability (odds ratio, 1.39 [95% CI, 1.33 to 1.47]; P < .001). Tumor group-specific associations persisted in colorectal, GIST, liver, and pancreatic tumors after multivariable adjustment.

Potential clinical actionability differs between EO and LO GI cancers in a tumor lineage-specific manner. Several major EO GI tumor groups appear relatively depleted of potentially actionable alterations, suggesting that the expanding therapeutic reach of precision oncology may not be distributed evenly across age-defined GI cancer populations and underscoring the need for EO-focused biomarker discovery and therapeutic development.