A single institute retrospective trial of concurrent chemotherapy with SIR-Spheres® versus SIR-Spheres® alone in chemotherapy-resistant colorectal cancer liver metastases.

BACKGROUND: The use of selective internal radiation therapy with yttrium 90 resin microspheres (SIR-Spheres®) in chemotherapy-resistant colorectal cancer liver metastases has been associated with favorable progression-free survival (PFS) and overall survival when given alone or concurrently with chemotherapy. We conducted a single institute retrospective trial to explore the potential impact of SIR-Spheres® with concurrent chemotherapy vs. SIR-Spheres® alone on liver PFS in patients with colorectal liver metastases (CRLM).

METHODS: Patients with 5-fluorouracil-refractory CRLM treated with SIR-Spheres® between 2009 and 2014 were identified. Patients were excluded if they received any chemotherapy/targeted regimen following radioembolization on which they did not previously progress. This strategy was adopted to minimize the impact of post-SIR-Spheres® systemic therapy bias on PFS.

RESULTS: Twenty-seven patients satisfied inclusion criteria and were included in this analysis. Patients' demographics were similar between the two treatment arms, except for the median number of prior therapies. No associated ≥ grade 3 toxicities were noted. Liver disease control rates were 84% and 14% on the SIR-Spheres® plus chemotherapy arms and SIR-Spheres® alone arms, respectively (P=0.001). Median PFS in the liver was 176 days in the SIR-Spheres® plus chemotherapy group vs. 91 days in the SIR-Sphere® alone group (P=0.0009). Median overall survival was 212 days in the SIR-Spheres® plus chemotherapy group vs. 154 days in the SIR-Spheres® alone group (P=0.1023).

CONCLUSIONS: In patients with 5-fluorouracil-refractory disease, SIR-Spheres® plus chemotherapy is associated with an increased liver disease control rate and a prolonged liver PFS in comparison with SIR-Spheres® alone.