The aim of this study was to assess the feasibility, safety and efficacy of percutaneous radiofrequency ablation of lung metastases from colorectal carcinoma using C-arm cone beam computed tomography (CBCT) guidance.

This single-center prospective observational study was performed from August 2013 to August 2016, and included consecutive patients referred for radiofrequency ablation of lung metastases from colorectal cancer. Radiofrequency ablation procedures were performed under C-arm CBCT guidance. Feasibility was assessed by probe accuracy placement, time to accurate placement and number of C-arm CBCT acquisitions to reach the target lesion. Safety was assessed by the report of adverse event graded using the common terminology criteria for adverse events (CTCAE-V4.0). Efficacy was assessed by metastases response rate using RECIST 1.1 and ¹⁸FDG-PET-CT tumor uptake at 6months.

Fifty-four consecutive patients (32 men, 22 women) with a mean age of 63±8 (SD) years (range: 51–81years) with a total of 56 lung metastasis from colorectal metastases were treated in a single session. The mean tumor diameter was 25.6±4.5 (SD)mm (range: 17–31mm). Median time to insert the needle into the target lesion was 10min (range: 5–25min). Median number of needles repositioning and C-arm CBCT acquisition per patient was 1 (range: 0–3) and 4 (range: 3–6) respectively. The accuracy for radiofrequency ablation probe placement was 2±0.2 (SD)mm (range: 0–9mm). Pneumothorax requiring chest tube placement occurred in one patient (CTCAE-V4.0 grade 3). At 6months, all patients were alive with tumor response rate of −27% and had no significant activity on the ¹⁸FDG-PET CT follow-up.

Percutaneous radiofrequency ablation of lung metastases from colorectal cancer under C-arm CBCT guidance is feasible and safe, with immediate and short-term results similar to those obtained using conventional CT guidance.