This study retrospectively compared long-term outcomes between two groups of breast cancer patients with malignant pleural effusion (MPE): those receiving only systemic therapy (ST) and those receiving ST following initial pleurodesis (P-ST). We identified 180 breast cancer patients from the National Cancer Center Hospital (Tokyo, Japan) database who had received ST and P-ST as an initial treatment for MPE between 1997 and 2008 for study inclusion. Pleural progression-free survival (PPFS) was defined as the time from ST in the ST group and from pleurodesis in the P-ST group to the first observation of pleural progression or death from any cause. Of the 180 patients, 78 received ST and 102 received P-ST after MPE diagnosis. Median duration of follow-up was 12.7 months (range 0.9-80.1 months). Median PPFS for the ST group and the P-ST group was 4.1 and 8.5 months, respectively. The difference in PPFS between the two groups was statistically significant (p < 0.001) and the hazard ratio after adjusting for prognostic factors in the P-ST group relative to the ST group was 0.24. Our results suggest that the efficacy of P-ST may be superior to that of ST alone with respect to local control of pleural effusions in breast cancer patients.