Background/Objectives: There is still no consensus as to whether patients with upfront resectable synchronous colorectal liver metastases (sCRLM) should receive neoadjuvant treatment prior to liver surgery. Two randomized controlled trials have assessed the role of peri-operative chemotherapy in sCRLM; neither have shown a survival benefit in the neoadjuvant group. The aim of this population-based study was to examine overall survival in patients treated with neoadjuvant chemotherapy and hepatectomy compared to patients who had upfront surgery.

Methods: This is a retrospective observational study between 2009 and 2017 containing data extracted from two Swedish national registries. Descriptive statistics and Cox regression analyses were employed. Results: In total, 2072 patients with sCRLM were treated with liver surgery between 2009 and 2017. A majority (n = 1238, 60%) were treated with neoadjuvant chemotherapy, and 834 patients (40%) had upfront surgery. Patients in the upfront surgery group were older (median age 70 compared to 65 years, p <= 0.001). Median overall survival in the upfront surgery group was 26 months (95% CI 23-29 months) compared to 57 months (95% CI 42-48 months) in the neoadjuvant group, log rank p <= 0.001. In the multivariable Cox regression analysis, age >= 70 years (HR 1.46, 95% CI 1.25-1.70), T category of primary cancer (HR 1.41, 95% CI 1.09-1.84), lymphatic spread of primary cancer (HR 1.68, 95% CI 1.41-1.99), and number of liver metastases (six or more metastases resulted in HR 2.05, 95% CI 1.38-3.01) negatively influenced overall survival. By contrast, adjuvant therapy was protective (HR 0.80, 95% CI 0-69-0.94), whereas neoadjuvant treatment compared to upfront surgery did not influence overall survival (HR 1.04, 95% CI 0.86-1.26).

Conclusions: Neoadjuvant treatment in sCRLM did not confer a survival benefit compared to upfront surgery.