There was limited information on the ideal surgical procedure for patients with colorectal cancer liver metastases (CRLM) who were having both their colons removed and their liver metastases removed at the same time.

Retrospective evaluations of CRLM patients from five locations were conducted. Intraoperative and postoperative results were among the short-term outcomes. The Clavien-Dindo classification was used to measure postoperative complications. Minor postoperative problems were classified as Grade I to II issues. Progression-free survival (PFS) and overall survival (OS) were the long-term results. The selection bias between colorectal resection first and liver resection first was eliminated using propensity score matching (PSM) and inverse probability of treatment weighting (IPTW).

There were 1,255 CRLM patients altogether. Body mass index (BMI) <24 kg/m2, the left hemicolon as the main location, non-bilobar liver metastasis distribution, and lack of preoperative chemotherapy were all shown to be substantially linked with the chance of colorectal resection first in the multivariable logistic regression analysis. After 1:1 PSM, there was no discernible difference between the liver and colorectal resection first groups. Patients who had liver resection first had comparable postoperative infection rates (15.0% vs. 16.0%, P = 0.735) compared to patients who had colorectal resection first. They also had longer operation times (305.0 [231.3-416.0] vs. 300.0 [225.0-374.0], P = 0.033), more intraoperative blood loss (200.0 [150.0-400.0] vs. 100.0 [100.0-300.0], P< 0.001), higher postoperative minor complication rate (28.7% vs. 20.7%, P = 0.023) and a higher postoperative ICU rate (14.7% vs. 8.7%, P = 0.022). When compared to patients who had liver resection first, individuals who had colorectal resection first had a comparable PFS (P = 0.702, median: 20.6 months vs. 16.6 months) and an unfavorable OS (P = 0.014, median: 48.5 months vs. 67.0 months). Colorectal resection first was not an independent predictor of PFS (hazard ratio [HR] = 0.986, 95% CI 0.831-1.170, P = 0.874), but it was a risk factor for OS in the IPTW-adjusted Cox proportional hazards regression analysis ( HR= 1.301, 95% CI 1.048-1.616, P = 0.017). Consistent findings were obtained via a Cox proportional hazards regression analysis with IPTW adjustment that included postoperative problems, operation duration, intraoperative blood loss, and postoperative chemotherapy into account. 

Patients who had colon resection first, although going against the “sterility principle,” did not have a higher postoperative infection incidence, had some better short-term outcomes, and had a comparable PFS to those who had liver resection first.