Usefulness of diagnostic laparoscopy with 5-aminolevulinic acid (ALA)-mediated photodynamic diagnosis for the detection of peritoneal micrometastasis in advanced gastric cancer after chemotherapy.

Abstract

Successful cases have shown that conversion surgery after chemotherapy improves the prognosis of advanced gastric cancer. However, it is necessary to carefully select patients who have no unresectable factors prior to surgery. We recently reported that diagnostic laparoscopy with photodynamic diagnosis using oral 5-aminolevulinic acid (ALA-PDD) is a promising tool for diagnosing early peritoneal metastasis in gastric cancer. We herein evaluated the usefulness of this technique for detecting peritoneal metastases of advanced gastric cancer after chemotherapy. Diagnostic laparoscopy using sequential white light (WL) and ALA-PDD observations was performed in 38 patients with advanced gastric cancer after chemotherapy. The sensitivity of ALA-PDD for detecting peritoneal disease was compared with that of WL. The relationship between the state of peritoneal metastasis assessed by ALA-PDD and a cytological examination of the peritoneal fluid was evaluated. Twelve of the 38 patients (32%) were diagnosed with peritoneal metastases by conventional laparoscopy. However, laparoscopy with ALA-PDD detected peritoneal metastases in 4 (11%) of the 26 remaining patients. Three of these 4 patients had negative cytological results from the evaluation of the peritoneal fluid. Diagnostic laparoscopy using ALA-PDD is a useful technique for detecting metastases and determining treatment strategies to select patients with advanced gastric cancer who have received chemotherapy.