Objective: To evaluate the long-term efficacy and prognostic factors of ultrasound-guided percutaneous radiofrequency ablation (RFA) for breast cancer liver metastasis (BCLM).
Methods: Between 2000 and 2015, 69 patients who underwent ultrasound-guided percutaneous RFA for BCLM and had regular follow-up examinations were included. All patients had undergone resection of the primary breast cancer and had received chemotherapy, endocrine therapy or both after surgery. The sample included two males and 67 females with an average age of 50.3 ± 10.0 years (31-76 y). The mean maximum diameter of metastatic lesions in the liver was 2.9 ± 1.4 cm (1.0-6 cm). Thirty-five patients had a single metastasis, while 34 patients had multiple liver metastases (2-5 lesions). Survival results were generated using Kaplan-Meier estimates and a multivariate analysis was performed using the Cox regression model.
Results: In total, 92 RFA sessions were performed and 135 BCLM lesions were treated. Major complications occurred in one of the 92 sessions (1.1%). Technical efficacy was achieved in 92.6% of lesions (125/135 lesions). Local tumor progression occurred in 11.6% (8/69) of patients and new intrahepatic metastasis occurred in 55.1% (38/69) of patients. From the time of initial RFA, the median overall survival was 26 months, and the one-, two-, three- and five -year survival rates were 81.8, 50.1, 25.3 and 11.0%, respectively. Based on the multivariate analysis, the following three factors were identified as independent prognostic factors for overall survival: tumor size (p = .017), positive estrogen receptor status (p = .009) and extrahepatic metastatic disease (p = .001). The median progression-free survival was 24 months, and the one-, two-, three- and five -year survival rates after RFA were 77.4, 47.0, 23.7 and 8.5%, respectively. Additionally, the independent prognostic factors for progression-free survival included tumor size (p = .011), ER positivity (p = .001), margin size (p = .017) and extrahepatic metastatic disease (p < .001).
Conclusion: The results of this study showed that RFA is a safe and locally effective method for the treatment of BCLM, especially in patients with lesions measuring less than 3 cm in diameter, a single liver metastasis, positive estrogen receptor status and no extrahepatic metastases. Also, patients with margin size >10 mm had no local tumor progression.
Keywords: Breast cancer; liver metastases; prognosis; radiofrequency ablation; survival analysis.