Phase III Trial Comparing Protracted Intravenous Fluorouracil Infusion Alone or With Yttrium-90 Resin Microspheres Radioembolization for Liver-Limited Metastatic Colorectal Cancer Refractory to Standard Chemotherapy

Abstract

Purpose: Liver dissemination is a major cause of mortality among patients with advanced colorectal cancer. Hepatic intra-arterial injection of the β-emitting isotope yttrium-90 (⁹⁰Y) bound to resin microspheres (radioembolization) delivers therapeutic radiation doses to liver metastases with minimal damage to adjacent tissues. Patients and Methods: We conducted a prospective, multicenter, randomized phase III trial in patients with unresectable, chemotherapy-refractory liver-limited metastatic CRC (mCRC) comparing arm A (fluorouracil [FU] protracted intravenous infusion 300 mg/m² days 1 through 14 every 3 weeks) and arm B (radioembolization plus intravenous FU 225 mg/m² days 1 through 14 then 300 mg/m² days 1 through 14 every 3 weeks) until hepatic progression. The primary end point was time to liver progression (TTLP). Cross-over to radioembolization was permitted after progression in arm A. Results: Forty-six patients were randomly assigned and 44 were eligible for analysis (arm A, n = 23; arm B, n = 21). Median follow-up was 24.8 months. Median TTLP was 2.1 and 5.5 months in arms A and B, respectively (hazard ratio [HR] = 0.38; 95% CI, 0.20 to 0.72; P = .003). Median time to tumor progression (TTP) was 2.1 and 4.5 months, respectively (HR = 0.51; 95% CI, 0.28 to 0.94; P = .03). Grade 3 or 4 toxicities were recorded in six patients after FU monotherapy and in one patient after radioembolization plus FU treatment (P = .10). Twenty-five of 44 patients received further treatment after progression, including 10 patients in arm A who received radioembolization. Median overall survival was 7.3 and 10.0 months in arms A and B, respectively (HR = 0.92; 95% CI, 0.47 to 1.78; P = .80). Conclusion: Radioembolization with ⁹⁰Y-resin microspheres plus FU is well tolerated and significantly improves TTLP and TTP compared with FU alone. This procedure is a valid therapeutic option for chemotherapy-refractory liver-limited mCRC.