Immunological Analysis and Clinical Effects of Intraabdominal and Intrapleural Injection of Lentinan for Malignant Ascites and Pleural Effusion

Authors: Masaaki Oka, Shigefumi Yoshino, Shoichi Hazama, Kouji Shimoda & Takashi Suzuki

Journal: Biotherapy

Study Design: Uncontrolled clinical trial

Participants: 16 patients with 20 malignant effusions (9 ascites, 11 pleural effusions)

Intervention: Intracavitary injection of lentinan (4 mg/week) for 4 weeks

Outcome Measures:

• Clinical response (disappearance or decrease of effusion, improvement of cytology class)
• Performance status (PS)
• Survival time
• Changes in lymphocyte subsets and functions of peripheral blood mononuclear cells (PBMC) and peritoneal or pleural exudate cells (PEC)
• Toxicity

Summary: The study investigated the effects of intracavitary lentinan injection on malignant effusions and immune responses. The results showed that 80% of the lesions demonstrated clinical responses, with improved performance status in some patients. The average survival time was longer in responders (129 days) compared to non-responders (49 days), although the difference was not statistically significant. No serious toxicities were observed. The study also found that lentinan injection decreased NK activity of PBMC but increased NK activity of PEC in responders. Anti-Daudi and lymphokine-activated killer (LAK) activity were also augmented or maintained after lentinan injection. The authors concluded that intracavitary lentinan injection could be a safe and effective treatment for malignant effusions, potentially by stimulating NK and cytotoxic T cell activities.