Long-term outcome of pleurodesis with OK-432 in metastatic breast cancer: a new risk model for success from an analysis of 75 cases

Malignant pleural effusion is a common and devastating complication of metastatic breast cancer. This occurs in about 30% of patients with metastatic breast cancer during the clinical course, and chemical pleurodesis is sometimes performed to relieve dyspnea. However, the long-term outcome of pleurodesis and factors affecting successful pleurodesis have not been clarified.

The aim of this analysis is to evaluate the long-term outcome of pleurodesis and to identify risk factors associated with success.

Data on 75 patients who had undergone chemical pleurodesis with OK-432 for pleural effusion due to metastatic breast cancer were reviewed retrospectively. The primary outcomes were success rate and pleural progression-free survival (PPFS) rate.

The median duration of follow-up was 134 days (range 8–975 days). During this period, 22 patients re-accumulated pleural fluid. The overall success rate was 70.5%. The 4-, 8- and 12-week PPFS rates were 88.0, 84.0 and 78.7% respectively. Multivariate analysis identified three unfavorable factors that were independently associated with unsuccessful pleurodesis, including estrogen-receptor negative status, a 24-h drainage volume of more than 100 mL before extubation and NSAID use. The PPFS rate at median follow-up was 93.5% in the low-risk group (n = 41, 0 or 1 unfavorable factor) and 55.1% in the high-risk group (n = 34, 2 or 3 unfavorable factors). The difference between the PPFS curves of the two risk groups was statistically significant (P < 0.001).

Pleurodesis for metastatic breast cancer was efficacious in controlling malignant pleural effusion. Our simple new risk model warrants further studies.