Photodynamic therapy of ascites tumours within the peritoneal cavity

A murine ascites tumour was treated with intraperitoneal haematoporphyrin derivative (HPD) and laser light (10mW, 514nm, Argon laser). HPD was given intraperitoneally 2 hours before 16 minute laser treatment. Uptake studies 2 hours after HPD injection showed 5-12 fold greater concentration of HPD in tumour cells than in 4 different normal tissues. A total of four HPD/laser treatments, given at 2 day intervals, resulted in 100% complete response; the cure rate was 85%. This study illustrates the effective use of intraperitoneal photodynamic therapy and opens the possibility of exploring different sensitizers, excitation wavelengths, and delivery systems in the treatment of human ascites tumours.