Histopathological growth patterns of resected non-colorectal, non-neuroendocrine liver metastases: a retrospective multicenter study.

Background: Distinct Histopathological Growth Patterns can be identified in liver metastases from melanoma, breast and colorectal cancers. For each of these distinct liver metastasis types the HGP has proven a biomarker for survival after partial hepatectomy, with the desmoplastic type marking favourable prognosis. Whether HGPs can be considered a pan-cancer phenomenon remains unknown. This study therefore evaluates the presence of HGPs and their prognostic value across non-colorectal non-neuroendocrine liver metastases.

Methods: A retrospective multicentre cohort study was performed in patients who underwent curative intent resection of non-colorectal non-neuroendocrine liver metastasis. HGPs were assessed on Haematoxylin and Eosin slides according to consensus guidelines and classified as desmoplastic or non-desmoplastic. Overall- and recurrence-free survival were evaluated using Kaplan-Meier and multivariable Cox regression analysis.

Results: In total, 132 patients with liver metastasis from 25 different tumour types were eligible for analysis, of which 26 (20%) had a desmoplastic HGP. Five-year OS and RFS (95%CI) were 53% (36-78%) versus 40% (30-53%), and 33% (19-61%) versus 15% (9-27%) for patients with desmoplastic compared to non-desmoplastic metastases, respectively (p = 0.031 & p = 0.004). On multivariable analysis (adjusted HR [95%CI]) a desmoplastic HGP was prognostic for both OS (0.46 [0.25-0.86]) and RFS (0.38 [0.21-0.69]).

Conclusions: This study demonstrates that HGPs apply to liver metastases across a wide variety of primary tumour origins. They hold a prognostic value in these cases, suggesting that HGPs could represent a pan-cancer biomarker for survival after surgical resection of liver metastases.