Comprehensive next-generation sequencing (NGS) reveals multiple primary colorectal carcinoma (MPCC)

Abstract

Abstract Multiple primary colorectal carcinoma (MPCC) is a rare clinical disease, which is difficult to distinguish from metastatic disease by histopathological approaches. Next-generation sequencing (NGS) have been applied to solve the problem of identifying multiple primary cancers. In the study, a rare case of a 63-year-old male patient was diagnosed with MPCC by targeted NGS, which was firstly missed diagnosed by radiological evaluation. The separated two tumors on the surface of the colorectal shared no same genomic alterations. Based on the wild-type KRAS detected in the unresected tumor, the patient benefited from the EGFR inhibitor (cetuximab), but developed novel mutations including KIF5B-RET fusion, which provides possible resistance mechanism to anti-EGFR therapy. Our case highlights the necessity of using genetic testing for primary tumor diagnosis and the application of serial plasma ctDNA profiling for dynamic disease monitoring.