SAFETY STUDIES FOR INTRAOPERATIVE PHOTODYNAMIC THERAPY

A new adjunctive therapy is needed for colorectal carcinoma surgery to decrease local recurrence rates. Photodynamic therapy (PDT) may be able to fulfil this role by activating the selective photosensitizer haematoporphyrin derivative (HPD) intraoperatively with laser light. This technique would necessitate the irradiation of normal tissues and therefore safety studies have been carried out in miniature pigs. Animals were photosensitized with HPD (5 mg kg -1), then 48 h later colonic anastomoses and ureters were irradiated with 50 J cm -2 of 510 nm-equivalent light. Anatomical, physiological and biochemical analyses were carried out, investigating both structure and function. Our results show that PDT applied in a potentially useful biological dose has no detrimental effect on the healing of anastomoses and ureteric structure and function. This work paves the way for intraoperative adjunctive PDT to be used effectively in man. © 1992 Baillière Tindall.