Next-generation laser-based photodynamic endoscopic diagnosis using 5-aminolevulinic acid for early gastric adenocarcinoma and gastric adenoma

Abstract

Background Photodynamic diagnosis (PDD) is an optical imaging technology based on the fundamental biological features of porphyrin metabolized in cancer cells. We reported the usefulness of laser-based photodynamic endoscopic diagnosis (LPDED) with 5-aminolevulinic acid (5-ALA) for early gastric cancers. However, the first-generation prototype endoscope system had the flaw that the images captured were rather dark. To overcome this, we constructed a nextgeneration endoscope system for LPDED. Methods We evaluated the usefulness of the next-generation prototype endoscope system, called Sie-P2, for brighter LPDED to detect early gastric cancer (EGC) and gastric adenoma. The 14 patients diagnosed with EGC and/or gastric adenoma who underwent endoscopic submucosal dissection (ESD) at our hospital between April 2018 and March 2019 were enrolled consecutively in this study. Patients were administered 5-ALA orally and LPDED was performed 3 h later. The primary endpoint was the presence of fluorescence in tumors when we performed LPDED. The secondary endpoint was to assess the adverse events related to each LPDED procedure. Results One patient was excluded because of a contraindication, while the remaining 13 patients (median 72 years, range 56-77; one female) with 16 lesions were assessed. There were 10 elevated lesions and 6 flat/depressed lesions; there were 10 EGCs and 6 adenomas. LPDED-fluorescence was detected in all 16 lesions (sensitivity 100%, 95% confidence interval 79-100%). Two cases showed temporary, though not substantial, elevation in blood liver function tests. Conclusion All lesions examined were LPDED-positive, indicating that the Sie-P2 system could be useful.

Photodynamic Diagnosis for the Identification of Intestinal-Type Gastric Cancers and High-Grade Adenomas

“…As there was a difference in the level of fluorescence among the 45 lesions, the PDD-positive lesions were divided into strongly PDD-positive (++) and weakly PDD-positive (+). Tumors were deemed PDD-positive (++) when the intense fluorescence and diffuse fluorescence were clearly greater compared to the background signal and that of the PDD-positive (+) samples ( 12 , 13 ). There were 21 PDD-positive (++) lesions and 24 PDD-positive (+) lesions ( Table 1 ).…”

“…Endoscopic PDD was performed 3 h after the oral administration of 20 mg/kg 5-ALA. For the in vivo fluorescence detection of PpIX accumulation, a Sie-P1video image endoscope system (Fuji Film Medical Co., Tokyo, Japan) consisting of a VP-0001 processor, an LL-4450-P1 light source, and an XG-0002-P1 scope or a Sie-P2 system (Fuji Film Medical Co.) with a VP-7000-P2 processor, an LL-7000-P2 light source, and an EG-L590ZW esophagogastroduodenoscopy scope was used ( 12 , 13 ). A 410-nm laser was used for blue-light excitation of PpIX to induce red fluorescence emittance.…”

Current Status of Photodynamic Diagnosis for Gastric Tumors

“…PDED was performed on 16 lesions in 13 patients, and all lesions (100%) were positive with PDED (Figure 3). Furthermore, compared to Sie-P1, the entire image was brighter and more easily seen [60]. Analysis of all gastric tumors in which PDED was performed using Sie-P1 and Sie-P2 showed fluorescence in 42 of 49 lesions in 43 cases (85.7%).…”

“…PDED was performed on 16 lesions in 13 patients, and all lesions (100%) were positive with PDED (Figure 3). Furthermore, compared to Sie-P1, the entire image was brighter and more easily seen [60]. Therefore, we developed Sie-P2, a prototype endoscope with further technical improvements, such as increasing the laser power and eliminating the cut filter on the tip of the scope to increase the contrast between the background and the tumor area.…”

“…In the prior studies, 85.7% (42/49) of gastric tumors exhibited fluorescence in PDED [58][59][60]. PDED is based on the fluorescence of the tumor, which enables objective evaluation independent of the endoscopist's experience, and is useful for tumor detection.…”