Introduction : Colorectal cancer harboring KRAS mutations are known to exhibit a high rate of vascular invasion and hematogenous metastases. Although it is generally accepted that non-anatomical resection (NAR) in colorectal liver metastasis (CRLM) is comparable to safety and efficacy compared to anatomical resection (AR) and does not affect the oncologic outcome, there are reports that AR has oncologic benefit in KRAS-mutated CRLM. This study aimed to compare survival outcomes between AR versus NAR resection for CRLM, according to KRAS mutational status.

Methods : 344 patients who underwent hepatic resection of CRLM with known KRAS mutational status were reviewed from 2007 to 2018. Among them, 117 KRAS mutated CRLMs and 227 KRAS wild type CRLMs were compared.

Results : Both KRAS wild type and mutated type, the size of the resected tumor, tended to be larger in the AR group than in the NAR group (p<0.001, respectively). In the short term surgical outcome, hospital stay was significantly longer in the AR group (15.65 vs. 11.27 days, p <0.001), and there was no difference between the two groups in estimated blood loss, postoperative complications, and 30-day mortality. There was no difference in disease-free survival (DFS) between AR and NAR in both the KRAS wild type and the mutated type (p=0.326, p=0.954, respectively). In addition, there was no difference in intrahepatic DFS between AR and NAR in both the KRAS wild type and the mutated type (p= 0.165, p=0.516, respectively).

Conclusions : Resection type was not associated with DFS and intrahepatic DFS in the KRAS mutated group.