Transvenous pulmonary chemoembolization and microwave ablation for lung metastases from breast cancer: a propensity score matching analysis.

Purpose: To compare the outcomes of patients with pulmonary metastases from breast cancer, who were treated with transvenous pulmonary chemoembolization (TPCE) and consecutive microwave ablation (MWA) with patients treated by TPCE alone.

Material and methods: This retrospective single-center study included patients with unresectable and/or non-responsive to systemic chemotherapy pulmonary metastases originating from breast cancer, treated by TPCE followed by MWA, in case of adequate response to TPCE, or by TPCE alone. The groups of patients were balanced using propensity score matching (PSM).

Results: A total of 97 patients met the inclusion criteria for this study. After PSM, 23 patients were included in the combination therapy group (Group 1) and 42 patients were included in the monotherapy group (Group 2). The median overall survival (OS) time was 33.6 months for Group 1 with a 2-year OS rate of 62%, and 20.2 months for Group 2 with a 2-year OS rate of 43%. There was no significant difference between the two groups regarding OS (p value: 0.429). The rate of progressive/recurrent disease was 17.4% (4/23) in Group 1 and 23.8% (10/42) in Group 2 (p value: 0.754). The number of metastases was the only significant factor for OS in all patients after PSM (p value: 0.032, HR: 1.016, 95% CI 1.001-1.031).

Conclusion: TPCE is an effective potential treatment for lung metastases of breast cancer, which can be performed alone or combined with MWA. Patients who responded to TPCE and received subsequent MWA demonstrated non-significant better OS and local tumor control.