Prognostic Significance of Basing Treatment Strategy on the Results of Photodynamic Diagnosis in Advanced Gastric Cancer.

BACKGROUND: We have previously reported that use of a staging laparoscopy (SL) combined with photodynamic diagnosis using 5-aminolevulinic acid (ALA-SL) improves sensitivity in detecting peritoneal dissemination in gastric cancer (GC). The purpose of this study was to examine the clinical significance of basing treatment strategies on the results of ALA-SL in patients with advanced GC.

PATIENTS AND METHODS: ALA-SL was performed on 113 patients with advanced GC prior to determination of their first course of treatment. According to the results of ALA-SL, patients were divided into four groups, including those classified as P0 (45%), ALA-P (12%), P1 plus P2 (23%), and P3 (20%). Patients with peritoneal metastases were subjected to chemotherapy. In addition, drug responders also received a gastrectomy. Treatment outcomes and patient characteristics stratified upon the results of ALA-SL were then analyzed.

RESULTS: The 3-year survival rates for patients in the P0, ALA-P, P1-2, and P3 groups were 73, 72, 49, and 6%, respectively. The survival estimates of patients classified as ALA-P via ALA-SL were very similar to those of P0 patients and were significantly better than those of P1-2 and P3 patients. Moreover, the false negative rate for ALA-SL-mediated detection of peritoneal metastasis at exploration was minimal (1/40, 2.5%), possibly due to the use of ALA.

CONCLUSIONS: ALA-SL may enhance the accuracy of diagnosis and contribute to therapeutic advantages in advanced GC. It should be introduced for advanced GC patients, especially females, as well as for individuals with high-stage tumors and/or tumors with diffuse-type histology.