Practice variation and outcomes of minimally invasive minor liver resections in patients with colorectal liver metastases: a population-based study

Introduction In 2017, the Southampton guideline stated that minimally invasive liver resections (MILR) should considered standard practice for minor liver resections. This study aimed to assess recent implementation rates of minor MILR, factors associated with performing MILR, hospital variation, and outcomes in patients with colorectal liver metastases (CRLM). Methods This population-based study included all patients who underwent minor liver resection for CRLM in the Netherlands between 2014 and 2021. Factors associated with MILR and nationwide hospital variation were assessed using multilevel multivariable logistic regression. Propensity-score matching (PSM) was applied to compare outcomes between minor MILR and minor open liver resections. Overall survival (OS) was assessed with Kaplan–Meier analysis on patients operated until 2018. Results Of 4,488 patients included, 1,695 (37.8%) underwent MILR. PSM resulted in 1,338 patients in each group. Implementation of MILR increased to 51.2% in 2021. Factors associated with not performing MILR included treatment with preoperative chemotherapy (aOR 0.61 CI:0.50–0.75, p < 0.001), treatment in a tertiary referral hospital (aOR 0.57 CI:0.50–0.67, p < 0.001), and larger diameter and number of CRLM. Significant hospital variation was observed in use of MILR (7.5% to 93.0%). After case-mix correction, six hospitals performed fewer, and six hospitals performed more MILRs than expected. In the PSM cohort, MILR was associated with a decrease in blood loss (aOR 0.99 CI:0.99–0.99, p < 0.01), cardiac complications (aOR 0.29, CI:0.10–0.70, p = 0.009), IC admissions (aOR 0.66, CI:0.50–0.89, p = 0.005), and shorter hospital stay (aOR CI:0.94–0.99, p < 0.01). Five-year OS rates for MILR and OLR were 53.7% versus 48.6%, p = 0.21. Conclusion Although uptake of MILR is increasing in the Netherlands, significant hospital variation remains. MILR benefits short-term outcomes, while overall survival is comparable to open liver surgery. Graphical abstract