PHOTODYNAMIC THERAPY FOR ESOPHAGEAL CANCER USING A 180-DEGREES WINDOWED ESOPHAGEAL BALLOON

Although delivery of uniform circumferential light is desirable during photodynamic therapy of advanced esophageal cancer in humans, early e sophageal cancer may need only targeted treatment. Studies were perfor med in the canine esophagus of eight animals to investigate whether us e of a ''windowed'' (shaded) centering balloon would improve targeted illumination of esophageal mucosa for photodynamic therapy. Shaded bal loons were developed with a a-cm-long, 360 degrees or 180 degrees clea r ''window.'' Photofrin 4 mg/Kg was used as the photosensitizer. Light at 630 nm was delivered at 300 J/cm or 600 J/cm. Isotropic probes pla ced on the balloon wall allowed real-time measurement and verification of relatively uniform light doses delivered to esophageal mucosa duri ng balloon photodynamic therapy. With the windowed balloon, targeted d elivery of photodynamic therapy was possible. Using the 180 degrees ba lloon, mucosa exposed to illumination was destroyed, whereas mucosa pr otected from light by the balloon shading was undamaged. Healing was c omplete and strictures did not occur. The shading of the balloon prote cted normal mucosa and prevents the formation of esophageal strictures . The ''windowed'' centering balloon provides a technology and techniq ue that allows targeted delivery of uniform light during esophageal PD T. (C) 1994 Wiley-Liss, Inc.