Primary tumor resection improves survival in colon cancer patients with unresectable liver only metastases.

BACKGROUND: The optimal management of colon cancer patients with unresectable liver-only metastases remains controversial. This study aimed to evaluate whether primary tumor resection confers a survival benefit in this population using data extracted from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: We identified patients diagnosed with colon cancer between 2018 and 2020 in the SEER database. After excluding those with extrahepatic metastases, multiple primary malignancies, or resectable liver lesions, a total of 1,533 patients with unresectable liver-only metastases were included. Among them, 400 underwent primary tumor resection and 1,133 did not. To reduce selection bias, propensity score matching (PSM) was performed, yielding two well-balanced cohorts of 167 patients each. Kaplan-Meier analysis was used to estimate overall survival (OS) and cancer-specific survival (CSS). Multivariable Cox proportional hazards regression determined independent prognostic factors, while logistic regression identified factors associated with receiving surgery. RESULTS: Before PSM, patients in the resection group were generally younger, had smaller tumors, and were more likely to receive chemotherapy than those without resection (all p < 0.05). After matching, baseline characteristics were comparable between groups. Kaplan-Meier curves showed significantly improved OS and CSS for the surgical group at 12, 24, and 36 months (p < 0.0001). In the multivariable Cox model, primary tumor resection independently predicted better CSS (HR = 0.409, 95% CI: 0.290-0.576, p < 0.001). Logistic regression revealed that T stage was significantly associated with the likelihood of undergoing surgery (p < 0.05). CONCLUSIONS: Primary tumor resection in patients with colon cancer and unresectable liver-only metastases is independently associated with improved survival. These findings support considering surgical intervention of the primary tumor as part of a comprehensive treatment strategy, although prospective studies are warranted to confirm these results.