Correlation of carcinoembryonic antigen with survival in patients with colorectal liver metastases receiving yttrium-90 radioembolization treatment.

e15509 Background: Colorectal liver metastases are a leading cause of cancer-related mortality in patients with colorectal cancer. Yttrium-90 (Y-90) radioembolization is a minimally invasive locoregional therapy offering potential survival benefits for patients with unresectable liver metastases. Despite its growing use, the prognostic factors influencing outcomes after Y-90 therapy remain poorly defined. This study aims to assess the clinical, laboratory, and tumor-specific factors that may impact survival following Y-90 treatment. Purpose: To assess the prognostic factors and associated clinical outcomes of patients receiving Y-90 radioembolization therapy for colorectal liver metastases. Methods: Single institution retrospective study of patients with colorectal liver metastases who received Y-90 radioembolization. Patients treated between 2010 and 2024 were included from our single institution cohort. Tumor characteristics, patient demographics, systemic treatment regimens, laboratory values, genomic tumor makeup and survival data were analyzed. Carcinoembryonic antigen (CEA) was evaluated at standardized pre- and post- treatment timelines. Kaplan-Meier survival estimation and multivariate Cox regression were evaluated. Results: 52 patients treated with Y-90 radioembolization fulfilled the inclusion criteria. Of the total cohort, those available patients who had documented pre- and post-Y-90 lab values available within 30 days prior to treatment and those with labs 30 days post-treatment were evaluated. Average age at diagnosis was found to be 62.1 years for all patients (38.5% female, 61.5% male). Decreased survival post Y-90 treatment was shown in patients with elevated post-treatment CEA (> 20 ng/mL). The median survival in patients with elevated CEA post-treatment was 8.2 months, as compared to 24.1 months in those patients with CEA ≤ 20 post-treatment (p=0.015). Additionally, decreased survival post Y-90 treatment was shown in patients who did not show a decrease in CEA level post-Y90. The median survival in patients with persistently elevated CEA post-treatment was 6.1 months, as compared to 19.1 months in patients who showed a decrease in CEA post-treatment (p=0.018). Patient demographics including gender, age and ethnicity were not shown to be significant in overall survival post-Y90 treatment (p-values >0.05). Conclusions: Post-treatment carcinoembryonic antigen value >20 ng/mL and relative decrease of CEA level post-Y90 are both significant prognostic factors in patients with colorectal liver metastases receiving Y90 radioembolization.