title: Evaluating the efficacy and safety of a novel endoscopic fluorescence imaging modality using oral 5-aminolevulinic acid for colorectal tumors.
abstract: OBJECTIVE
  Five-aminolevulinic acid (5-ALA) is being increasingly used for photodynamic diagnosis and therapy of various types of tumors including brain, urologic, and other neoplasias. The use of 5-ALA to treat Barrett's carcinomas has been documented, but its clinical effectiveness for diagnosis of gastrointestinal tumors, particularly early cancers, remains unknown.
  
  
  METHODS
  The aim of our feasibility study was to evaluate the visibility of colorectal tumors using endoscopic fluorescence imaging (EFI) after oral administration of 5-ALA. The lesions identified by direct visualization and by the spectrums produced using EFI modality with 5-ALA were compared to the clinicopathologic features of resected specimens.
  
  
  RESULTS
  Twenty-three patients with a total of 27 known colorectal lesions were enrolled in the study. The median tumor size was 30 mm (range 10 - 75). Eleven of the lesions were flat or depressed lesions and 16 were sessile. Red fluorescence was observed in 22 out of 27 lesions. Red fluorescence was negative in 4 out of 11 flat or depressed lesions. In comparison with histopathologic findings, the rates of red fluorescence visibility were 62.5 % in low-grade intraepithelial neoplasia, 77.8 % in high-grade neoplasia, and 100 % in submucosal carcinoma. Red fluorescence visibility increased with the degree of dysplasia. There were no significant adverse events identified in this study.
  
  
  CONCLUSIONS
  This feasibility study using EFI with 5-ALA demonstrated high visibility of superficial colorectal neoplasia. EFI with 5-ALA appears to be a novel, safe technique for improving real-time colorectal tumor imaging.
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Eriko So
authors.initials: ES
authors.lastname: Tsuruki
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Abe
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takamaru
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yamada
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Sakamoto
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Matsuda
authors.affiliation: Pathology Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sekine
authors.affiliation: Pathology Division, National Cancer Center Hospital, Tokyo, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Taniguchi