Background: We report here a case where no everolimus pleural diffusion was evidenced at the same time of pleural progression of a metastatic breast cancer treated with everolimus and exemestane.
Case description: A 69-year-old woman was diagnosed in October 2006 with stage III invasive ductal breast adenocarcinoma. After nine months of everolimus and exemestane treatment, she presented with a pleural progression. Everolimus concentration was measured in blood and in pleural fluid. Residual blood concentration was at 9.1 ng/mL, while no everolimus was observed in the pleural fluid.
Management and outcome: Due to inefficacy of everolimus in this patient, she was switched to palbociclib and fulvestrant.
Conclusion: Everolimus seems to have a poor diffusion in the pleural fluid.
Keywords: Breast cancer; everolimus; pleural progression.