Barcelona, Spain—The first randomized study prospectively investigating the efficacy of radiofrequency ablation (RFA) added to standard systemic treatment in patients with unresectable colorectal cancer (CRC) liver metastases revealed progression-free survival (PFS) and overall survival (OS) benefits, according to Theo J.M. Ruers, MD, PhD, Department of Surgery, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Ziekenhuis, Amsterdam.
In RFA, a needle electrode is guided through imaging into a tumor, where high-frequency electrical current produces thermal ablation. Dr Ruers presented the study findings at the 2015 European Society for Medical Oncology World Congress on Gastrointestinal Cancer.
Although RFA is being used increasingly in patients with unresectable CRC liver metastases, prospectively gathered data from investigations in defined therapeutic settings are scarce. The phase 2 EORTC 40004/CLOCC study included 119 patients randomized to 6 months of systemic treatment with or without RFA. Approximately 75% of the patients received systemic treatment with FOLFOX (leucovorin, fluorouracil, and oxaliplatin) and approximately 17% received bevacizumab.
The patients had ≤9 unresectable CRC liver metastases and no extrahepatic disease. The maximum size of RFA-treated lesions was 4 cm. Patients were included if they had received previous chemotherapy as long as at least stable disease had been achieved. The median age was approximately 65.5 years (approximately 67% were male). The patients had a median of 4.5 lesions, and 14% had received chemotherapy for metastatic disease. Overall, 52.6% of the patients received RFA alone, and 47.5% received RFA plus resection. The mean hospital time was 4.8 days.
Previous reports showed 61.7% OS in the group receiving systemic treatment plus RFA and 57.6% among those receiving systemic treatment only. In addition, at 4.4 years of follow-up, the median PFS was 16.8 months for the RFA group versus 9.9 months for the group receiving systemic treatment only (hazard ratio [HR], 0.63; P = .025).
After a median follow-up of 9.7 years, PFS was 2% in the group receiving systemic therapy alone and 22.3% when RFA was added (HR, 0.57; 95% confidence interval [CI], 12.7-33.7; P = .005). The 8-year OS rates were 8.8% for systemic therapy alone and 35.9% for RFA (HR, 0.58; 95% CI, 0.38-0.88; P = .010).
Dr Ruers emphasized that progressive disease was the main cause of death in fewer patients who had RFA—56.7% versus 81.4% for systemic therapy only. At the last assessment, 10.2% of patients treated with systemic therapy only were alive compared with 35.0% of patients receiving systemic therapy plus RFA.
The liver was the site of first progression in 32.6% of patients whose disease advanced after RFA and in 69.6% of patients receiving systemic therapy. Among 170 total lesions treated with RFA, progression occurred at the radiofrequency site in 11 (6.5%) lesions.
“Current analysis on long-term outcome shows that RF [radiofrequency] in addition to systemic therapy is associated with a significant benefit in PFS and OS in patients with unresectable colorectal liver metastases, when compared to standard systemic therapy alone,” he said.
“Despite the small sample size, the findings encourage the use of ablative techniques as a treatment modality in patients with unresectable colorectal liver metastases,” he observed.