Preliminary report of photodynamic therapy for intraperitoneal sarcomatosis

Introduction: Sarcomatosis is the disseminated intraperitoneal spread of sa rcoma. It is a condition for which there is no effective treatment. Photody namic therapy (PDT) is a cancer treatment modality that uses a photosensiti zing agent and laser light to kill cells. We report our preliminary Phase I I clinical trial experience using PDT for the treatment of intraperitoneal sarcomatosis. Methods: From May 1997 to December 1998 eleven patients received twelve PDT treatments for intraperitoneal sarcomatosis. Photofrin (R) 2.5 mg/kg was a dministered intravenously 48 hours before surgical debulking to a maximum r esidual tumor size of less than 5 mm. Light therapy was administered at a f luence of 2.5 J/cm(2) of 532 nm green light to the mesentery and serosa of the small bowel and colon; 5 J/cm(2) of 630 nm red light to the stomach and duodenum; 7.5 J/cm(2) of red light to the surface of the liver, spleen, an d diaphragms; and 10 J/cm(2) of red light to the retroperitoneal gutters an d pelvis. Light fluence was measured with an on-line light dosimetry system . Response to treatment was evaluated by abdominal CT scan at 3 and 6 month s, diagnostic laparoscopy at 3 to 6 months, and clinical examination every 3 months. Results: Adequate tumor debulking required an omentectomy in eight patients (73%), small bowel resection in seven patients (64%), colon resection in f our patients (36%), splenectomy in one patient (9%), and a left spermatic c ord resection in one patient. Five patients (45%) have no evidence of disea se at follow-up (range, 1.7-17.3 months), including patients at 13.8 and 17 .3 months examined by CT. Two patients (18%) died from disease progression. Four patients (36%) are alive with disease progression. Toxicities related to PDT included substantial postoperative fluid shifts with volume overloa d, transient thrombocytopenia, and elevated liver function tests. One patie nt suffered a postoperative pulmonary embolism complicated by adult respira tory distress syndrome (ARDS). Conclusions: Debulking surgery with intraperitoneal PDT for sarcomatosis is feasible. Preliminary response data suggest prolonged relapse-free surviva l in some patients. Additional follow-up with more patients will be necessa ry for full evaluation of the added benefit of PDT and aggressive surgical debulking in these patients.