The following is a summary of “Microsatellite instability is associated with worse overall survival in resectable colorectal liver metastases,” published in the FEBRUARY 2023 issue of Surgery by Turner, et al.

For a study, researchers sought to investigate the relationship between microsatellite instability (MSI) and overall survival (OS) in colorectal liver metastases (CRLM). The National Cancer Database (NCDB) was used to collect data on patients who had undergone metastasectomy for CRLM. 

Among the 2,743 patients identified, 84.4% (n=2,316) had microsatellite stable tumors (MSS), while 15.6% (n=427) had MSI. There were no significant differences in sex, race, or underlying comorbidities between the two groups. However, MSS patients had lower rates of high-risk pathologic features and higher rates of receiving multi-agent chemotherapy. The median OS for the MSS group was 41.1 months compared to 33.2 months for the MSI group (P < 0.01), as determined by Kaplan-Meier analysis. Multivariate analysis showed that MSI status remained associated with worse OS (HR: 1.21, 95% CI: 1.01–1.46, P=0.04).

In conclusion, the study confirmed that MSI status is a useful biomarker for guiding clinical decision-making in patients with CRLM due to its association with poor prognosis. The data from the NCDB supported the evidence that MSI is associated with improved OS in locoregional colorectal cancer but negatively affects OS in CRLM. Further studies were needed to determine the phenomenon’s underlying mechanism and explore the potential of MSI as a predictive biomarker for response to treatment.

Source: americanjournalofsurgery.com/article/S0002-9610(22)00504-9/fulltext