Prognostic impact of metastatic sites and its metastasectomy in colorectal cancer: a retrospective analysis from a single institution.

Purpose: This study aims to evaluate the prognostic influence of different metastatic sites and the effect of surgical resection on survival. Additionally, it explores how anatomical location influences prognosis before and after metastasectomy.

Methods: This retrospective study included 999 mCRC patients treated at Taipei Veterans General Hospital from 2013 to 2019. Survival outcomes across liver, lung, peritoneal, and distant lymph node (LN) metastases were analyzed using Kaplan-Meier and Cox regression models.

Results: Prognosis varied significantly by metastatic site. For single-site metastases, distant LN metastases had the longest OS (36.8 months), followed by lung (35.5 months), liver (26.5 months), and peritoneal metastases (21.5 months; p = 0.001). Lung metastases showed the longest PFS (11.7 months), followed by distant LN (10.8 months), peritoneal (9.8 months), and liver (9.1 months; p = 0.031). Surgical resection significantly improved OS (HR = 0.477, p < 0.001). With metastasectomy, OS was comparable for liver, lung, and distant LN metastases (p = 0.288), while peritoneal metastases had significantly poorer outcomes (HR = 2.208, p = 0.001). In patients without surgery, OS was significantly poorer across all metastatic sites, with lung metastases demonstrating the most favorable prognosis (OS = 31.9 months) and statistically significant differences compared to liver, peritoneal, and distant LN metastases (p < 0.001).

Conclusion: The prognosis of mCRC varies by metastatic site. Surgical resection significantly improves survival for liver, lung, and distant LN metastases but is less effective for peritoneal metastases. Surgery reduces the prognostic disparity among resectable sites except for peritoneal seeding.