Overall survival analysis of the FOXFIRE prospective randomized studies of first-line selective internal radiotherapy (SIRT) in patients with liver metastases from colorectal cancer.
Sharma RA., Wasan HS., Van Hazel GA., Heinemann V., Sharma NK., Taieb J., Ricke J., Mills J., Tait NP., Boardman P., Peeters M., Findlay MPN., Virdee PS., Moschandreas J., Gebski V., Love S., Gray A., Gibbs P.
3507 Background: The FOXFIRE, SIRFLOX and FOXFIRE-Global (FF-SF-FFG) randomized studies evaluated the efficacy of combining first-line chemotherapy for metastatic colorectal cancer (mCRC) with selective internal radiotherapy (SIRT) using yttrium-90 resin microspheres in patients with liver metastases. The studies were designed for prospective, combined analysis of overall survival (OS). Methods: FF-SF-FFG randomized (1:1) chemotherapy-naïve mCRC patients (performance status 0/1) with liver metastases not suitable for curative resection/ablation. Arm A was oxaliplatin-based chemotherapy (mFOLFOX6/ OxMdG) ± investigator-chosen biologically targeted agent. Arm B was the same systemic therapy (oxaliplatin dose modification) + single treatment SIRT with cycle 1/2 of chemotherapy. Primary tumor in situ and/or limited extra-hepatic metastases were permitted. Minimum sample size was 1075 patients (HR 0.8, 80% power, two-sided 5% significance). Secondary outcomes included PFS, liver-specific PFS and response rate. Apart from safety, outcomes were analysed on intention-to-treat population using meta-analytic methods of pooled individual patient data. Results: Between 2006 and 2014, 1103 patients were randomized in 14 countries. Median age was 63 years (range 23-89); median follow-up 43.3 months. There were 844 deaths. There was no difference in OS (HR 1.04; 95% CI 0.90-1.19, p= 0.609) or PFS (HR 0.90, CI 0.79-1.02, p= 0.108) between Arms. Objective response rate ( p= 0.001) and liver-specific progression (HR 0.51, CI 0.43-0.62, p< 0.001) were significantly more favorable in Arm B. Patients in Arm B had higher risk of non-liver progression as first event (HR 1.98, CI 1.53-2.58, p< 0.001). Grade 3-5 adverse events were more common in Arm B (74.0%) than A (66.5%), p= 0.009. In health status questionnaires, EQ-5D utility scores were not significantly different between Arms at 6, 12 or 24 months. Conclusion: Despite higher response rates and improved liver-specific PFS, the addition of SIRT to first-line oxaliplatin-fluorouracil chemotherapy for patients with liver-only and liver-dominant mCRC did not improve OS or PFS. Clinical trial information: 83867919.