Photodynamic diagnosis using 5-aminolevulinic acid during gastrectomy for gastric cancer.

BACKGROUND AND OBJECTIVES: Five-aminolevulinic acid (ALA) has received much attention recently as a new-generation photosensitive substance for photodynamic diagnosis (PDD). This study aimed to investigate the feasibility of intraoperative PDD using ALA to identify gastric cancer.

METHODS: Intraoperative PDD was carried out in 26 lesions of 21 patients with gastric cancer. Before surgery, 1.0 g of ALA solution was given orally through a stomach tube. After tumor resection, resected specimens were investigated by an endoscopic PDD system, and red fluorescence-positive lesions were compared with the pathological result.

RESULTS: Red fluorescence was detected in 15 lesions of 11 patients. The sensitivity, specificity, and accuracy of PDD using ALA in detecting gastric cancer were 57.7, 100, and 66.7%, respectively. The incidence of laparoscopic surgery was significantly lower in the PDD-positive group than in PDD-negative cases (18.2% vs. 60.0%; P = 0.049), while that of intestinal type tumor was significantly higher in PDD-positive compared to PDD-negative patients (93.3% vs. 27.3%; P < 0.001).

CONCLUSIONS: Fluorescence navigation by PDD provides good visualization and detection of gastric cancer lesions, and might be particularly useful for intestinal type gastric cancer. Thus, PDD using ALA seems to be a promising diagnostic tool for gastric cancer.