Percutaneous radiofrequency ablation of inoperable pulmonary metastases from colorectal cancer

Abstract

3502 Background: This current study was an open, prospective and nonrandomized phase II study, which critically evaluated the prognostic parameters for local disease-free survival (DFS) and overall survival (OS) in patients who underwent percutaneous radiofrequency ablation (RFA) for inoperable colorectal pulmonary metastases (CRPM). Methods: The inclusion criteria were patients who had inoperable CRPM, due to number, distribution, poor performance status or patients’ refusal to accept surgery. The exclusion criteria were lesions > 6 per hemithorax; diameter of metastases > 5 cm; bleeding diathesis; and/or significantly compromised lung function. All patients underwent percutaneous RFA with a radiological clear margin of at least 2 cm. The end-points of this study were local DFS and OS, determined from the time of RFA intervention. Ten clinical and six treatment-related prognostic parameters were assessed in univariate and multivariate analyses. All patients were reviewed at one week, one month and every three months thereafter with chest CT. Fifty-five patients entered into the study. The follow-up was complete and the median follow-up was 24 months (6 to 40). Results: The median local DFS was not reached and 2-year local DFS was 57%. Univariate analysis demonstrated that largest size of lung metastasis, location of lung metastases, post-RFA CEA at 1 month and 3 months were significant for local DFS. In multivariate analysis, largest size of lung metastasis of ≤ 3 cm and post-RFA CEA of ≤ 5 ng/ml at 1 month were independently associated with an improved local DFS. The median OS was 33 months (4 to 40), with 1-, 2-, and 3-year survival of 85%, 64% and 46%, respectively. Univariate analysis demonstrated that interval between the diagnoses of colorectal cancer and pulmonary metastasis; largest size of lung metastasis and location of lung metastases were significant for OS. In multivariate analysis, only size of lung metastasis of ≤ 3 cm was independently associated with an improved OS. Conclusions: Percutaneous RFA of inoperable CRPM may have a useful role in patients with a lesion of ≤ 3 cm. No significant financial relationships to disclose.