Shape-Memory Alloy Loop Snare for Endoscopic Photodynamic Therapy of Early Gastric Cancer

Background and Study Aims: Photodynamic therapy (PDT) has proved effective in the treatment of gastric cancer, but there is room for improvement. To achieve the technical goal of carrying out endoscopic PDT, endoscopists need to determine the precise area for laser irradiation at adequate dosages. This report describes the use of a shapememory alloy (SMA) loop snare as a useful tool in endoscopic PDT.

Patients and Methods: Eleven patients with biopsyproved early gastric cancer were treated with endoscopic PDT after intravenous injection of Photofrin II (2 mg/kg b.w.). Five patients underwent PDT using the SMA loop snare, and six underwent PDT without the use of the device. Cancer lesions smaller than 2 cm in diameter were irradiated with an excimer-dye laser (4 mJ, 80 Hz, 630 nm) for 20 min.

Results: All five patients (100 %) treated with PDT using the SMA loop snare, and four of the six patients (67 %) treated with PDT without use of the SMA loop snare, showed complete remission.

Conclusions: The SMA loop snare routinely forms a circle 2 cm in diameter, covering an area of 3.14 cm², and makes it possible to mark and calculate the precise area of cancerous lesions for irradiation at appropriate dosages. The findings of this study suggest that the SMA loop snare is an effective tool for PDT in early gastric cancer.

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