Early-onset colorectal cancer patients exhibit a distinct molecular fingerprint: insights from a large-scale NGS study of 1209 patients

Background: Early-onset colorectal cancer (EO-CRC, ≤50 years of age) exhibits unique clinical and biological characteristics when compared with average-onset CRC (AO-CRC), but its overall molecular profile is still not well studied. Materials and methods: We retrospectively analysed 1209 patients with metastatic CRC profiled using FoundationOne® CDx, a clinically validated next-generation sequencing assay targeting 324 cancer-related genes. Patients were classified as EO-CRC (n = 298) or AO-CRC (n = 911). Genomic alterations, including amplifications, deletions, and point mutations, were compared between the groups. Overall survival (OS) was assessed through 1 : 1 propensity-score-matched cohorts adjusted for key clinical and molecular covariates. Results: Patients with EO-CRC showed a unique genomic profile marked by a higher incidence of MYC, RAD21, GNAS, and MAPK1 amplifications. They also experienced CDKN2B loss and recurrent mutations, including APC∗, NRAS Q61L, PIK3CA, and TP53 G266V. These variations were statistically significant, indicating different oncogenic pathways. When comparing matched analyses, patients with EO-CRC had notably poorer OS than those with AO-CRC: 35 months versus 41 months in the overall matched group (P = 0.0326), 35 months compared with 44 months among Eastern Cooperative Oncology Group performance status 0 patients (P = 0.0026), and 27 months versus 44 months in the RAS/BRAF-mutated subgroup (P = 0.0024). Conclusions: Patients with EO-CRC show a distinctive and biologically aggressive molecular profile, marked by significant changes in genes associated with cell proliferation and responses to environmental stress. These observations support the classification of EO-CRC as a potentially distinct clinical entity and suggest that personalised treatment strategies tailored to age-related molecular profiles warrant further investigation.