Efficacy and Tolerability of Selective Internal Radiotherapy With Yttrium-90 as Consolidation Treatment After Chemotherapy in Metastatic Colorectal Cancer.

Background: Selective internal radiotherapy (SIRT) with yttrium-90 (Y-90)-labeled resin microspheres may have a role in consolidating the response to chemotherapy in patients with metastatic colorectal cancer unamenable to resection after assessment of the best response to first-line chemotherapy.

Patients And Methods: This was a retrospective analysis of outcomes in patients who had received SIRT as consolidation therapy after one or more lines of chemotherapy. Eligible patients were 18 years or older, had confirmed colorectal liver metastases, and had disease unsuitable for surgical resection or local ablation with curative intent. The primary endpoint was progression-free survival.

Results: Sixty-eight patients with colorectal liver metastases were treated with at least one SIRT procedure after receiving one or more lines of chemotherapy. Median progression-free survival was significantly longer in patients who received SIRT after prior first-line chemotherapy compared to those who received SIRT after two or more lines of chemotherapy (9 vs. 3 months, respectively; hazard ratio = 0.07; 95% confidence interval, 0.02854‒0.2039; P < .001), and in patients with liver-only disease compared to those who had extrahepatic metastases (6.4 vs. 4.1 months, respectively; hazard ratio = 0.57; 95% confidence interval, 0.34-0.95; P = .0318). There were no grade 3 or higher adverse events.

Conclusion: SIRT represents a valid option for the treatment of colorectal liver metastases. Earlier use of SIRT may provide a greater survival benefit compared to that afforded by the procedure when used in salvage settings.