Clinical and flow cytometry characteristics of malignant pleural effusions in patients after intracavitary administration of methylprednisolone acetate

Ten patients with recurrent pleural effusions due to advanced cancer were treated by intracavitary methylprednisolone acetate (Depo-Medrol [DM], Upjohn, Kalamazoo, MI). They received one to six courses of DM (median, three courses per patient) with doses ranging from 80 to 160 mg per course. Effusion cells were cryopreserved before and during DM installation for subsequent determination of ploidy by flow cytometry. Pleural effusion in all three patients with advanced breast cancer resolved and did not reaccumulate throughout follow-up for 11+, 10+, and 8+ months. Pleural effusion in a patient with metastatic gastric cancer and in two of four patients with adenocarcinoma of unknown origin partially resolved. Altogether six of ten patients (60%) subjectively and objectively benefited from this therapy. All patients tolerated the treatment well with no local or systemic side effects. Flow cytometry showed a reduction in ploidy of effusion cells in all three patients with breast cancer, from a peak mean channel of 6C to nearly 2C after therapy. Transient reduction of ploidy was seen also in the effusion of a patient with unknown primary tumor associated with clinical improvement. The clinical and laboratory data reported offers initial evidence that DM when instilled into the pleural cavity after incomplete thoracentesis may act as effective palliative therapy either alone or in combination with other anticancer agents.