TOLERANCE OF SMALL-BOWEL ANASTOMOSES IN RABBITS TO PHOTODYNAMIC THERAPY WITH DIHEMATOPORPHYRIN ETHERS AND 630 NM RED-LIGHT

Photodynamic therapy (PDT) is being evaluated in experimental clinical trials in patients with peritoneal malignancies. Some patients requir e partial small bowel resection with re-anastomosis prior to PDT becau se of bulky tumor or focal involvement of the small bowel by tumor. To assess the safety of PDT in this setting, the tolerance of small bowe l anastomoses in New Zealand white rabbits to PDT with dihematoporphyr in ethers (DHE) and 630 nm light was studied. With conventional DHE do ses of 1.5-2.5 mg/kg given 24 hours prior to surgery and light doses o f 0-20 J/cm(2) of 630 nm light, no adverse effects were seen on the he aling of small bowel anastomoses. Higher photosensitizer doses of 10 m g/kg and 20 mg/kg in conjunction with 20 J/cm(2), however, induced fai lure and breakdown of fresh anastomoses in 2/3 and 4/4 animals, respec tively. (C) 1993 Wiley-Liss, Inc.