Staging laparoscopy using ALA-mediated photodynamic diagnosis improves the detection of peritoneal metastases in advanced gastric cancer

Background This study evaluated the usefulness of photodynamic diagnosis (PDD) using oral 5‐aminolevulinic acid (ALA) for the detection of peritoneal metastases in advanced gastric cancer. Method First, the numbers of peritoneal metastatic nodules that were visible under conventional white light (WL) and ALA‐induced fluorescence (ALA‐F) were quantified in a mouse model of peritoneal metastasis to compare the tumor detection rate. Next, staging laparoscopy (SL) using ALA‐PDD was performed in 13 advanced gastric cancer patients with serosa‐invading tumors, and the detection sensitivity of ALA‐PDD was compared to the observations using WL. Results The tumor detection rate using ALA‐F was significantly higher than the detection rate using WL (72% vs. 39%, respectively, P