Histopathological investigation of colon liver metastases - which factors affect survival after surgery?

Novel therapeutic options have improved prognosis for patients with colonic liver metastases (CLM) over the last decades. Despite this, the challenge to select and stratify patients for optimal treatment regimen persists. This study aimed to evaluate established and novel histopathological features and investigate the impact on overall survival (OS) and recurrence in patients undergoing surgery for CLM.

Two hundred and sixty patients who underwent resection of CLM with curative intent 2006-2017 were included in the study. Clinicopathological characteristics were retrieved from patient medical records. The following histopathological parameters were investigated: vascular/lymphatic invasion, perineural invasion, tumor regression grade (TRG), tumor growth pattern, pseudocapsule and acellular mucin. Histopathological traits were correlated to OS.

Vascular and lymphatic invasion, as well as perineural invasion, significantly correlated with an adverse prognosis hazard ratio (HR) = 1.7, 95% confidence interval (CI) 1.23-2.40 and HR = 1.7, 95% CI 1.20-2.51, respectively. Results retrieved from the study could not propose any novel explorative histopathological features (TRG, tumor growth pattern, pseudocapsule and acellular mucin) to be of significant value as comes correlation with patient OS.

Classical histopathological characteristics of previously reported influence on survival were confirmed, while more novel factors that has been proposed, like tumor growth pattern, tumor regression and grade and presence of a pseudocapsule, were not. Further studies are thus needed to identify better ways of understanding the impact of tumor microenvironment and tumor biology on patient outcome and not at least for stratification and improved treatment response.