Prognostic significance of poorly differentiated clusters and tumor budding in colorectal liver metastases.

BACKGROUND: Histomorphological features have been described as prognostic factors after resection of colorectal liver metastases (CLM). The objectives of this study were to assess the prognostic significance of tumor budding (TB) and poorly differentiated clusters (PDC) among CLM, and their association with other prognostic factors. METHODS: We evaluated 229 patients who underwent a first resection of CLM. Slides stained by HE were assessed for TB, PDC, tumor border pattern, peritumoral pseudocapsule, peritumoral, and intratumoral inflammatory infiltrate. Lymphatic and portal invasion were evaluated through D2-40 and CD34 antibody. RESULTS: Factors independently associated with poor overall survival were nodules>4 (P = 0.002), presence of PDC G3 (P = 0.007), portal invasion (P = 0.005), and absence of tumor pseudocapsule (P = 0.006). Factors independently associated with disease-free survival included number of nodules>4 (P < 0.001), presence of PDC G3 (P = 0.005), infiltrative border (P = 0.031), portal invasion (P = 0.006), and absent/mild peritumoral inflammatory infiltrate (P = 0.002). PDC and TB were also associated with histological factors, as portal invasion (TB), peritumoral inflammatory infiltration (PDC), infiltrative border, and absence of tumor pseudocapsule (TB and PDC). CONCLUSIONS: This is the first study demonstrating PDC as a prognostic factor in CLM. TB was also a prognostic factor, but it was not an independent predictor of survival.