Defining the surgical management for non-colorectal liver metastases.

Background: Surgical resection is indicated for resectable colorectal liver metastases (CLM), but it is controversial for non-colorectal liver metastases (NCLM). This study aimed to compare survival outcomes of patients with resection of NCLM versus CLM and to identify prognostic factors for resection of NCLM.

Methods: Consecutive patients who underwent surgical resection of liver metastases at Queen Mary Hospital, Hong Kong from January 1989 to December 2019 were retrospectively reviewed. Patients with resected NCLM were compared to those with CLM. Overall and recurrence-free survival were determined. Subgroup analyses with patients grouped according to the year of liver resection, from 1989 to 2004 and from 2005 to 2019, were conducted. Univariate and multivariate analyses were performed to identify prognostic factors.

Results: Among 674 patients included, 151 (22.4%) had NCLM while 523 (77.6%) had CLM. There were no statistically significant differences in median overall survival (65.2 vs 43.6 months, p = 0.555) and recurrence-free survival (12.5 vs 11.7 months, p = 0.425). The 1-year, 3-year, 5-year and 10-year overall survival rates were 89.8% vs 91.5%, 59.4% vs 58.8%, 50.6% vs 38.7% and 34.1% vs 26.3% in NCLM and CLM groups, respectively. Subgroup analyses demonstrated no statistically significant difference in overall survival between resection of NCLM versus CLM in both time intervals. In the NCLM group, better overall survival was found in liver metastasis of gastrointestinal stromal tumour (GIST) origin (hazard ratio (HR) 0.138, p = 0.003) and with a longer time interval from resection of primary tumour to resection of NCLM (HR 0.982, p = 0.042). Poor prognostic factors were presence of blood transfusion (HR 5.588, p = 0.013) and post-operative complications of Clavien-Dindo Grade IIIa or above (HR 74.853, p = 0.003).

Conclusions: Surgical resection of NCLM had comparable survival outcomes with CLM. With appropriate patient selection, the indication of liver resection could be expanded to NCLM.