Differences in clinical characteristics and mutational pattern between synchronous and metachronous colorectal liver metastases

Peng Zheng,* Li Ren,* Qingyang Feng,* Dexiang Zhu,* Wenju Chang, Guodong He, Meiling Ji, Mi Jian, Qi Lin, Tuo Yi, Ye Wei, Jianmin Xu Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China *These authors contributed equally to this work Purpose: To investigate differences in clinical characteristics and mutational patterns between synchronous and metachronous colorectal liver metastases (CLMs). Patients and methods: From June 2008 to December 2014, patients with RAS wild-type CLMs treated at Zhongshan Hospital, Fudan University were included. DNA extracted from formalin-fixed paraffin-embedded tissue of primary tumors was sequenced with next-generation sequencing for single-nucleotide polymorphism of 96 genes according to custom panel. Mutations were compared between synchronous and metachronous liver metastases and correlated with clinical characteristics. Results: A total of 161 patients were included: 93 patients with synchronous CLM and 68 patients with metachronous CLM. Patients with metachronous CLM were obviously elder. For pathology of primary tumors, synchronous CLMs were larger in size, poorly differentiated, and more frequently local advanced and lymph node positive. For evaluation of liver metastases, synchronous CLM had more and larger metastatic lesions. The median number of mutations in synchronous CLMs was significantly higher than in metachronous group (22 vs. 18, p