P-352 Comparison of KRAS status between primary colorectal tumor and metastasis or recurrent tumor

Previous NGS experiments showed that distinct parts of the same tumor different mutation profiles. Additionally, primary tumors and their metastases can differ in mutational pattern. In this study, we compare KRAS status between colorectal cancer tissue recurrent/metastatic sites. Four patients with metastatic adenocarcinoma were screened for mutations by Idylla automated testing on two tissues belonging to patient before treatment (primary vs. metastatic/ 2 site sections/ recurrent tumor). screening perfect concordance (G12 KRASwtrespectively). One had a codon 146 colon no tissue, nor nodule metastases. Another has sigmoid K117N liver metastasis biopsy. Even if high is noted according literature, passenger could change deal, will not be sufficient therapeutic decision.