KRAS and metastatic neoplasm: Although, the presence of CTC detected by the CellSearch® system did correlate significantly with OS, 88 days (95 % CI: 27–206) CTC positive vs 393 days CTC negative (95 % CI: 284–501), CTC were detected in only 20 % of patients, the majority of which had metastatic disease, whereas KRAS mutant cfDNA was detected in patients with both resectable and advanced disease.