Introduction : Colorectal cancer (CRC) is associated with frequent distant metastases. Traditional surgical option for colorectal liver metastasis (CRLM) was a staged operation. And with advances of surgical techniques, devices, perioperative management and chemotherapeutic agents, CRLMs are now believed to be curable by operation. We analyze the differences of perioperative and oncologic outcome between simultaneous and staged operation.

Methods : Four hundred fifty six patients who underwent hepatic resection for known CRLM between January 2001 and December 2014 were retrieved from a retrospective database at our institution. Simultaneous resection was defined as co-operation between colorectal resection and liver resection. And staged operation was defined as colon resection was performed first and additional chemotherapy was followed.

Results : There were no statistically significant differences except ASA, preoperative chemotherapy state, number of metastatic tumor, liver resection margin (p = 0.034, p=0.001, p = 0.001, and p = 0.017, respectively). Only major liver resection showed statistically significant difference in multivariate analysis for postoperative complication (p = 0.018). In the multivariate analysis for disease-free survival and overall survival, there was a statistically significant increased risk of recurrence and poor prognosis in patients who had primary colorectal cancer histologic grade with poorly differentiated or mucinous adenocarcinoma, over 3 numbers of liver metastases, surgical margin of < 0.1 cm.

Conclusions : This study showed that simultaneous resections present similar major complication rates and oncologic outcomes compared with staged resection for synchronous CRLM. Simultaneous resection for synchronous CRLM appears to be feasible and safe.