"Two-stage resection of synchronous liver metastases in colorectal cancer leads to a survival benefit: a retrospective comparative cohort study".

Purpose: Colorectal cancer is the third most common cancer worldwide, with 15-25% of patients presenting synchronous liver metastases (UICC stage IV). Surgical resection remains crucial, but the optimal sequence for managing synchronous metastases is debated. This study evaluates the impact of different surgical strategies on survival in colorectal cancer patients with liver-only metastases (CRLM) and identifies factors influencing mortality.

Methods: This retrospective cohort study analyzed CRLM patients from German cancer registries in Brandenburg and Berlin from 2017 to 2022, grouped by surgical treatment sequence: simultaneous primary tumor resection (PTR) and liver resection, PTR before liver resection, or liver resection before PTR. Kaplan-Meier and Cox regression analyses evaluated overall survival (OS) and the impact of systemic therapy and patient characteristics.

Results: Among 23,394 colorectal cancer patients, 209 met inclusion criteria. Simultaneous resection was performed in 45% (N = 93), PTR before liver resection in 43% (N = 90), and liver resection first in 12% (N = 26). PTR before liver resection showed the best 5-year OS (68% vs. 53% for simultaneous surgery; HR 0.44, 95% CI = 0.22-0.88, p = 0.020). Simultaneous resection had the highest 30-day mortality (6.5%, N = 6). Postoperative chemotherapy significantly improved 5-year OS (66% vs. 57% for no chemotherapy; HR 0.45, 95% CI = 0.22-0.95, p = 0.036). Excluding 30-day mortality, survival differences diminished.

Conclusion: Primary tumor resection before liver resection appears to improve long-term survival in CRLM patients. Simultaneous resection should be carefully considered due to increased mortality, particularly in older patients with lower performance status undergoing major liver surgery. Postoperative chemotherapy enhances survival, emphasizing the need for tailored treatment strategies.