A total of 21 studies were included in the review (n=2,984, range 40 to 665): 13 studies clinical series and eight non-randomised comparative studies. Radiofrequency ablation site recurrence rates following percutaneous treatment ranged from 9% to 42% and following open radiofrequency ablation ranged from 5% to 14%. Median time to local tumour progression ranged from 1.5 to 39 months and median follow-up from 17 to 68 months.
Median and 5-year overall survival ranged from 24 to 59 months and 18% to 40% when calculation began after time of radiofrequency ablation treatment (12 studies) and from 37 to 63 months and 21% to 54% (six studies) from the time of diagnosis of CLM. Median and 5-year overall survival ranged from 36 to 45 months and 27% to 30% (five studies) after radiofrequency ablation combined with resection and for resection alone ranged from 41 to 80 months and 48% to 71% (six studies). Median progression-free survival after radiofrequency ablation alone ranged from six to 13 months (five studies) and the proportion of patients with progression free survival at two years ranged from 17% to 55% (five studies).
Following open radiofrequency ablation, complication rates ranged from 13% to 27% and major complication rates from 3.5% to 13% (six studies). Following percutaneous radiofrequency ablation, complication rates ranged from 1.8% to 13% and major complication rates from 0.9% to 7% (11 studies). Mortality rates were 0 to 3.7% following open radiofrequency ablation (six studies) and 0% following percutaneous radiofrequency ablation (11 studies). Comparative studies indicated significantly improved overall survival following radiofrequency ablation versus chemotherapy alone (one study), radiofrequency ablation plus chemotherapy versus radiofrequency ablation alone (two studies) and up-front radiofrequency ablation versus radiofrequency ablation following second-line chemotherapy (one study).