Objectives: Malignant pleural effusion, a common complication seen in advanced lung cancer patients, is often treated with intrapleural administration of chemical agents. In Japan, OK-432, a biological response modifiers, which activates the cytotoxic activity of lymphocytes and boosts antitumor immunity, is among the most frequently used chemical agents. The purpose of this study was to determine, in a case-control study, whether or not the rate of lymphocytes in malignant pleural effusion (lymphocyte rate) influences the therapeutic efficacy of intrapleural OK-432.
Patients and Methods: We enrolled 20 lung cancer patients with malignant pleural effusion treated with intrapleural OK-432 who were admitted to our hospital between January 2000 and December 2004. Therapeutic efficacy was assessed from the response rate, duration of chest drainage after treatment with intrapleural OK-432, time to progression of malignant pleural effusion, and survival time.
Results: Response rate in patients who had a high lymphocyte rate (the High lymphocyte rate group) was significantly higher than in patients who had a low lymphocyte rate (the Low lymphocyte rate group). Lymphocyte rate did not correlate with duration of chest drainage after treatment with intrapleural OK-432, time to progression of malignant pleural effusion, or survival time.
Conclusions: The lymphocyte rate in malignant pleural effusion influences the response rate to treatment by intrapleural OK-432. In the High lymphocyte rate group, intrapleural OK-432 for malignant pleural effusion was effective. We conclude that intrapleural OK-432 is useful for malignant pleural effusion patients with a high lymphocyte rate before treatment.