EDITORIALS and PDT Combination Therapy for Ovarian Cancer: The Play's the Thing

The prognosis for women diagnosed with advanced-stage epithelial ovarian cancer is poor, with fewer than one-third of patients surviving 5 years. Locally advanced pelvic tumors are often associated with diffuse peritoneal carcinomatosis and bulky tumor lesions involving the omentum, bowel, mesentery, and diaphragmatic surface. Even after aggressive cytoreductive surgery and platinum-based chemotherapy, most of these patients experience local progression or recurrence. The reasons for treatment failure probably relate to diffi culties inherent to surgery within the peritoneal cavity, problems related to administering cytotoxic agents to the tumor cells in cytotoxic concentrations, and the ability of ovarian cancer cells to develop resistance to standard chemotherapies. In this issue of the Journal, del Carmen and colleagues ( 1 ) present evidence that intraperitoneal administration of C225, a humanized murine monoclonal antibody directed against the epidermal growth factor (EGF) receptor (EGFR), and benzoporphyrin derivative monoacid-A (BPD) – based photodynamic therapy (PDT) act synergistically to prevent or inhibit tumor cell growth and extend survival in a murine model of ovarian cancer peritoneal metastasis. In these studies ( 1 ) , mice were injected intraperitoneally with human ovarian cancer-derived NIH:OVCAR-5 cells and subjected to PDT using BPD on days 10 and 20 after tumor cell inoculation. C225 was administered intraperitoneally on days 11, 14, 17, and 19 after tumor cell inoculation. As compared with mice treated with either C225 or PDT alone, mice treated with combined PDT + C225 showed a decrease in mean tumor burden as measured on day 21 after tumor cell inoculation and an increase in overall survival when mice were followed up to day 180, with three of nine C225 + PDT mice achieving cure of disease.