Abstract
BACKGROUND: Histopathologic growth patterns (HGPs) of colorectal liver metastases (CRLM) have emerged as potential prognostic biomarkers, though their clinical significance remains under investigation. The objective is to evaluate the prognostic value of HGPs on recurrence-free survival (RFS) and overall survival (OS) in patients undergoing liver resection for CRLM. PATIENTS AND METHODS: This was a retrospective analysis of the OSLO-COMET randomized controlled trial, where 280 patients underwent laparoscopic or open parenchyma-sparing liver resection for CRLM between February 2012 and February 2016. Patients eligible for long-term analysis and with available histological material were included. HGPs were categorized as desmoplastic, pushing, replacement, or mixed, according to international consensus guidelines. Kaplan-Meier and Cox proportional hazards models were used to evaluate associations between HGPs and survival. RESULTS: A total of 239 patients were included. Desmoplastic HGP was present in 43.5% of patients and associated with significantly better outcomes. Median RFS was 31 months for desmoplastic versus 9, 10, and 11 months for replacement, pushing, and mixed groups, respectively (p = 0.002). Five-year OS was 62% for desmoplastic, 59% for replacement, 55% for mixed, and 39% for pushing HGP (p = 0.036). In multivariable analysis, HGP, lymph node status, and extrahepatic disease were independent predictors of RFS. Age, tumor size, ECOG score, and extrahepatic metastasis significantly impacted OS. CONCLUSIONS: Replacement, pushing and mixed HGPs were associated with poor RFS, although replacement and mixed patterns showed better OS after treatment of recurrences. Desmoplastic HGP was independently associated with better RFS and OS following resection for CRLM.