Comprehensive landscape of FGFR variations and prognosis revelance in colorectal cancer from circulating tumor DNA and tissue gene analyses in 2083 patients.

278 Background: FGFR genomic alterations have been identified, and several FGFR inhibitors are approved for various malignancies, including bladder and cholangiocarcinoma. However, limited studies have shown FGFR alterations and their prognostic impact in colorectal cancer (CRC). Methods: This retrospective analysis involved tissue and blood samples from a single-institute cohort (The Sixth Affiliated Hospital of Sun Yat-sen University) of stage I-IV CRC patients from 2014 to 2024. FGFR genomic alterations were analyzed using tissue NGS and plasma ctDNA. Disease-free survival (DFS) for stages I-III and progression-free survival (PFS) for stage IV were compared between FGFR-altered and negative CRC patients, matched in a 1:2 ratio. Validation of genomic alterations and their prognostic impact was conducted using cBioPortal and TCGA data. Results: FGFR alterations were found in 7.89% of 608 tissue samples and 10.95% of 2083 ctDNA samples. The most frequent alteration was FGFR1 amplification in all cohorts, along with FGFR2 p.R165W and FGFR3 p.A634T mutations in ctDNA. FGFR alterations correlated with younger age, left-sided colon tumors, adenocarcinomas, poor differentiation, advanced TNM staging, and multi-organ metastasis. Prognostic analysis showed a higher proportion of FGFR alterations in stage IV patients (66.23% vs. 59.14%), lower rates of no evidence of disease (NED) (6.62% vs. 17.68%), and significantly shorter PFS (median 17 vs. 20 months, HR 2.184, p=0.007). In stages I-III, FGFR-altered patients also had a lower NED rate (79.22% vs. 82.19%) and significantly shorter DFS (median 13 vs. 29 months, HR 2.833, p=0.002). Among frequent alterations, FGFR1 amplification was significantly associated with poor prognosis (PFS 17 vs. 20 months, HR 2.221, p=0.014; DFS 13 vs. 29 months, HR 2.964, p=0.002), while others showed no significant correlation. In stage IV patients receiving bevacizumab, FGFR1 alteration was linked to significantly shorter PFS (p=0.0021). KEGG analysis indicated FGFR1 was associated with angiogenesis pathways. FGFR alteration profiles and prognostic outcomes were consistent across tissue samples, ctDNA analyses, and databases. Conclusions: Our study outlines the genomic landscape and prognostic significance of FGFR in CRC, highlighting FGFR1 amplification as the dominant alteration. FGFR alterations were associated with poorer outcomes, as reflected in lower NED rates and shorter DFS and PFS. FGFR1 amplification was notably linked to reduced DFS and PFS, and it correlated with shorter PFS in patients receiving bevacizumab, indicating a potential link to resistance against bevacizumab. ctDNA n=2083 Tissue genen=608 cBioPortal Databasen=6998 FGFR Total 228/10.95% 48/7.89% 528/8.0% FGFR1 76/3.65% 29/4.77% 264/4.0% FGFR2 78/3.74% 10/1.64% 125/1.9% FGFR3 104/4.99% 10/1.64% 139/2.1%