Histopathological growth patterns and positive margins after resection of colorectal liver metastases

BACKGROUND: Histopathological growth patterns (HGPs) of colorectal liver metastases (CRLM) may be an expression of biological tumour behaviour impacting the risk of positive resection margins. The current study aimed to investigate whether non-desmoplastic growth pattern (non-dHGP) is associated with a higher risk of positive resection margins after resection of CRLM. METHODS: All patients treated surgically for CRLM between January 2000 and March 2015 at the Erasmus MC Cancer Institute and between January 2000 and December 2012 at the Memorial Sloan Kettering Cancer Center were considered for inclusion. Positive resection margin (R1) was defined as tumour cells at the resection margin. RESULTS: Of all patients (n=1302) included for analysis, 13% (n=170) had positive resection margins. Factors independently associated with positive resection margins were the non-dHGP (odds ratio (OR): 1.79, 95% confidence interval (CI): 1.11-2.87, p=0.016) and a greater number of CRLM (OR: 1.15, 95% CI: 1.08-1.23 p