Clinical impact of preoperative liver MRI in the evaluation of synchronous liver metastasis of colon cancer.

Objectives: To investigate whether additional MRI including gadoxetic acid enhancement is associated with survival rate (SR) in patients with synchronous liver metastasis of colon cancer (sCLM), compared with patients assessed only with CT.

Methods: Fifty-two patients underwent only CT (CT group) and 65 underwent additional MRI (CT+MRI group) for preoperative work-up of sCLM. In the CT+MRI group, the discrepancy between CT and MRI was analyzed. The 5-year SR was compared between the groups, and affecting factors were investigated. The inverse probability treatment weighting analysis (IPTW) adjusted by propensity scores was performed.

Results: In the CT+MRI group, 44 (67.7%) showed a discrepancy in the number of sCLMs between CT and MRI. MRI detected 39 additional sCLMs initially missed on CT in 26 patients. The number of detected sCLMs was better correlated with the pathologic findings in the CT+MRI group than in the CT group (p = 0.008). The estimated 5-year SR in the CT+MRI group was 70.8%, while that in the CT group was 48.1%. On adjusted multivariate analyses after the IPTW, the CT+MRI group showed a significantly lower risk of overall mortality than the CT group.

Conclusion: Additional preoperative evaluation by MRI allowed us to more precisely detect sCLM and was associated with a better SR.

Key Points: • CT+MRI group showed significantly higher 5-year survival rates than CT group. • CT+MRI group was an independent prognostic factor of overall mortality. • MRI facilitates more accurate detection and better lesion characterization. • MRI selected better candidates for curative treatment. • The benefits of MRI were reflected by better survival.