Encapsulated histopathological growth pattern of colorectal liver metastases predicts prolonged survival after repeat liver resection for recurrence

The encapsulated histopathological growth pattern (HGP) of colorectal liver metastases (CRLMs) has been reported as a favorable prognostic factor. However, its prognostic relevance in patients undergoing treatment for recurrence after liver resection remains unclear. This study aimed to evaluate the impact of encapsulated HGP on time to surgical failure (TSF) following liver resection, and to assess whether encapsulated HGP at initial resection is associated with outcomes after repeat resection for recurrence. We retrospectively analyzed 272 patients who underwent initial liver resection for CRLMs. HGPs were classified and their associations with postoperative outcomes were examined. 61 patients were classified as having encapsulated HGP. Patients with encapsulated HGP had significantly longer TSF after liver resection than those with non-encapsulated HGP (p < 0.01). Multivariate analysis identified encapsulated HGP as an independent factor for improved TSF (Hazard ratio: 0.35, p < 0.01). Recurrence occurred less frequently in encapsulated HGP than in non-encapsulated HGP (63.9% vs 79.2%, p = 0.02). In addition, patients with encapsulated HGP had a lower incidence of multi-organ recurrence and a higher repeat resection rate for recurrence (64.1% vs 45.6%, p < 0.01). Among patients with repeat liver resection for recurrent CRLMs, post-recurrence survival was significantly longer in encapsulated HGP than in non-encapsulated HGP (p = 0.01) and encapsulated HGP at initial resection was identified as an independent factor of favorable survival after repeat liver resection (Hazard ratio: 0.09, p = 0.04). Encapsulated HGP was associated with improved TSF following liver resection for CRLMs. HGPs at initial resection may predict survival after repeat liver resection for recurrent CRLMs.