Radioembolization as a Salvage Therapy for Heavily Pretreated Patients With Colorectal Cancer Liver Metastases: Factors That Affect Outcomes.

Background: In this study we assessed the efficacy and factors that affect outcomes of radioembolization (RE) using yttrium-90 resin microspheres in patients with unresectable and chemorefractory colorectal cancer liver metastases (CLM).

Patients And Methods: After an institutional review board waiver of approval, a review of a Health Insurance Portability and Accountability Act-registered, prospectively created and maintained database was performed. Data on patient demographic and disease characteristics, RE treatment parameters, and additional treatments were evaluated for significance in predicting overall survival (OS) and liver progression-free survival (LPFS). Complications were evaluated according to the National Cancer Institute Common Terminology Criteria for adverse events.

Results: From September 2009 to September 2013, 53 patients underwent RE at a median of 35 months after CLM diagnosis. Median OS was 12.7 months. Multivariate analysis showed that carcinoembryonic antigen levels at the time of RE ≥ 90 ng/mL (P = .004) and microscopic lymphovascular invasion of the primary (P = .002) were independent predictors of decreased OS. Median LPFS was 4.7 months. At 4 to 8 and 12 to 16 weeks after RE, most patients (80% and 61%, respectively) according to Response Evaluation Criteria in Solid Tumors (RECIST) had stable disease; additional evaluation using PET Response Criteria in Solid Tumors (PERCIST) led to reclassification in 77% of these cases (response or progression). No deaths were noted within the first 30 days. Within the first 90 days after RE, 4 patients (8%) developed liver failure and 5 patients (9%) died, all with evidence of disease progression.

Conclusion: RE in the salvage setting was well-tolerated, and permitted the administration of additional therapies and led to a median OS of 12.7 months. Evaluation using PERCIST was more likely than RECIST to document response or progression compared with the baseline assessment before RE.