Different Effects of KRAS Gene on Recurrence for Right- and Left-sided Colorectal Liver Metastases Undergoing Radiofrequency Ablation

Objective: To investigate the association of KRAS mutations with recurrence in patients with colorectal liver metastases (CLM) undergoing radiofrequency ablation (RFA) according to the primary tumor location. Methods : CLM patients with a known KRAS gene status who underwent RFA were enrolled from January 1, 2012 to December 31, 2018. Clinicopathological data, recurrence, and survival dates were evaluated retrospectively. Results: 164 patients (mean age: 58.0 + 9.8 years, range: 34–83) who underwent percutaneous RFA of 325 CLM (mean sizes: 2.2 + 1.0 cm, range: 0.7–5.0) were included in the study; Patients (30.7%) in the KRAS mutation group had LTP, which was significantly higher than in patients with KRAS wild-type (14.6%) ( p = 0.013). Of the 126 (76.8%) patients with recurrence after RFA, 101 (61.6%) had intrahepatic recurrence, while 88 (53.7%) had extrahepatic recurrence. Among patients with left-sided colorectal cancer (CRC), intrahepatic recurrence rates were higher among patients with KRAS mutation than among patients with the wild type KRAS (77.2% vs 52.5%, p =0.003); the median intrahepatic recurrence-free survival (RFS) was worse in KRAS mutation patients (25 vs 15 months, P=0.007). In patients with right-sided CRC, there was no significant difference in intrahepatic recurrence between the KRAS wild-type and KRAS mutation groups (P＞0.05). Conclusions: KRAS status is associated with recurrence of CLM after RFA depending on primary tumor location. Advances in knowledge: KRAS mutation had worse intrahepatic recurrence-free survival after RFA of CLM among patients with left-sided CRC, but was not significantly different in recurrence among patients with right-sided CRC.