Percutaneous radiofrequency ablation (RFA) or robotic radiosurgery (RRS) for salvage treatment of colorectal liver metastases.

BACKGROUND Stereotactic radiation therapy is an evolving modality to treat otherwise unresectable liver metastases. In this analysis, two local therapies: 1) single session robotic radiosurgery (RRS) and 2) percutaneous radiofrequency ablation (RFA) were compared in a total of 60 heavily pretreated colorectal cancer patients. METHODS Thirty patients with a total of 35 colorectal liver metastases not qualifying for surgery that were treated in curative intent with RRS were prospectively followed. To compare efficacy of both treatment modalities, patients treated with RFA during the same period of time were matched according to number and size of the treated lesions. Local tumor control, local disease free survival (DFS), and freedom from distant recurrence (FFDR) were analyzed for efficacy. Treatment-related side effects were recorded for comparison. RESULTS The median diameter of the treated lesions was 33 mm (7-53 mm). Baseline characteristics did not differ significantly between the groups. One- and two-year local control rates showed no significant difference but favored RRS (85% vs. 65% and 80% vs. 61%, respectively). A significantly longer local DFS of patients treated with RRS compared to RFA (34.4 months vs. 6.0 months; p < 0.001) was found. Both, median FFDR (11.4 months for RRS vs. 7.1 months for RFA p = 0.25) and the recurrence rate (67% for RRS and 63% for RFA, p > 0.99) were comparable. CONCLUSION Single session RRS is a safe and effective method to treat colorectal liver metastases. In this analysis, a trend towards longer DFS was seen in patients treated with RRS when compared to RFA.