Surgical resection for multiple liver metastasis of colorectal cancer: Is there a limit in number and procedure?

[Background] Significance of surgical treatment for multiple (metastasis from colorectal cancer) mCRC is under debate.
[Aim] To clarify a limit in number and in procedure for multiple mCRC based on the dual institution in Japan and France.
[Method] From the clinical data base of our department (564 cases), the (recurrence free survival) RFS was calculated in more than 10 mCRC by open liver resection. The efficacy of repeat resection and predictor for recurrence were assessed. Then, the outcomes for operation in mCRC were compared to the high volume laparoscopic unit in France (associated institute: 784 cases) about 3 issues. (1) Surgical strategy for bilateral multiple mCRC, (2) RFS, (3) Efficacy for endoscopic surgery in multiple mCRC.
[Results] The 82% of patients found recurrence within 1-year in patients with 10 or more mCRC. In repeat resection, 5 or more tumors (Odds: 8.8, 95% CI: 3.6-88.3) and the interval until recurrence (500 days) were independent predictors for survival. Even though, some limitations in the number and tumor distribution were found in laparoscopic resection, 5Y-OS is comparable to open resection (p=0.451), and operation time (p=0.001) postoperative hospital stay was shorter in laparoscopic resection (p=0.004).
[Conclusion] It is not a good surgical indication for 10 or more mCRC. Laparoscopic resection for mCRC has benefit for less than 5 tumors.