RESUMO
BACKGROUND: Emerging evidence supports tumor tissue-based comprehensive genomic profiling (CGP) in metastatic colorectal cancer (mCRC). Data on liquid biopsy-based circulating tumor DNA (ctDNA) CGP are scarce and mainly retrospective. Prospective comparison between the two tests is not currently available. METHODS: The CAPRI 2-GOIM trial investigates efficacy and safety of ctDNA-driven, cetuximab-based, sequence of three treatment lines in patients with RAS/BRAFV600E wild type (WT) mCRC, as determined by local laboratory. Before first-line therapy, CGP is performed with FoundationOne (F1) CDx and F1 Liquid (F1L) CDx (324 genes) on tumor tissue DNA and plasma ctDNA, respectively. RESULTS: For 2/207 (0.96%) patients, no ctDNA was detected by F1L CDx. No patient displayed tumor fraction (TF) below 1%, whereas elevated ctDNA (TF≥10%) was detected among 140/205 (68.3%) patients. 1013 genomic variants were identified. F1L CDx found KRAS, NRAS or BRAFV600E alterations in 19 patients, whose tumors were classified as RAS/BRAFV600E WT by local laboratory. Both F1 CDx and F1L CDx were available for 164/205 (80%) patients. Concordance of 61.4% between the two tests was observed. Concordance increased to 72.7% for F1L CDx with TF ≥10%. Concordance for genes potentially involved in anti-epidermal growth factor receptor (EGFR) resistance was found in 137/164 (83%) patients, increasing to 91.5% for F1L CDx with TF ≥10%. A higher number of genomic alterations was detected by F1L CDx compared with F1 CDx, including 6 cases with KRAS and NRAS alterations. Overall, 109/205 (53.2%) patients displayed at least one actionable genomic alteration (I to IIIB), according to the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT). CONCLUSION: Baseline liquid biopsy-based CGP is feasible, it has high concordance with tumor tissue-based CGP, it could better recapitulate tumor heterogeneity, and it is clinically informative by identifying additional actionable genomic alterations in approximately half of RAS/BRAFV600E WT mCRC patients.