AIM:To prospectively investigate the effi cacy of the revised Vienna Classifi cation for diagnosing colorectal epithelial neoplastic lesions in cold biopsy specimens.METHODS:Patients were selected for inclusion if they had colorectal epithelial lesions that were not considered suitable for direct endoscopic resection.These included colorectal polyps ≥ 10 mm and lesions suspected of being carcinomas capable of invading the colorectal submucosa or beyond,including strictures,based on the cold biopsies obtained from each lesion prior to resection.We investigated the relationship between diagnoses based on cold biopsy samples using the revised Vienna Classification and resected specimens of the same lesions,and the therapeutic implications of diagnoses made using the revised Vienna Classification.The same cold biopsy specimens were also examined using the Japanese Group Classifi cation guidelines,and compared with the resected specimens of the same lesions for reference.RESULTS:A total of 179 lesions were identified.The sensitivity,specificity,positive and negative predictive values of the revised Vienna Classification for distinguishing between intramucosal lesions and submucosal invasive carcinomas in cold biopsy specimens was 22.2%,100%,100%,and 71.4%,respectively,and for distinguishing between intramucosal lesions and those invading the submucosa or beyond was 59.7%,100%,100%,and 37.6%,respectively.The sensitivity,specificity,positive and negative predictive values of the Japanese Group Classification for distinguishing between intramucosal lesions and submucosal invasive carcinomas in cold biopsy specimens was 83.3%,91.4%,83.3%,and 91.4%,respectively,and for distinguishing between intramucosal lesions and those invading the submucosa or beyond was 95.1%,91.4%,97.9%,and 82.1%,respectively.A total of 137 of 144 carcinomas that had invaded the submucosa or beyond and three high-grade intraepithelial neoplasias were diagnosed as “carcinoma” using the Japanese Group Classif ication system.CONCLUSION:The revised Vienna Classifi cation for cold biopsy specimens has high positive predictive value in the diagnosis of colorectal carcinoma invasive to the submucosa or beyond. AIM: To prospectively investigate the effi cacy of the revised Vienna Classifi cation for diagnosing colorectal epithelial neoplastic lesions in cold biopsy specimens. METHODS: Patients were selected for inclusion if they had colorectal epithelial lesions that were not considered suitable for direct endoscopic resection. These included colorectal polyps ≥ 10 mm and lesions suspected of being carcinomas capable of invading the colorectal submucosa or beyond, including strictures, based on the cold biopsies obtained from each lesion prior to resection. We investigated the relationship between diagnoses based on cold biopsy samples using the revised Vienna Classification and resected specimens of the same lesions, and the therapeutic implications of diagnoses made using the revised Vienna Classification. The same cold biopsy specimens were also examined using the Japanese Group Classifi cation guidelines, and compared with the resected specimens of the same lesions for reference.RESULTS: A total o f 179 lesions were identified. sensitivity, specificity, positive and negative predictive values ​​of the revised Vienna Classification for Distinguishing between intramucosal lesions and submucosal invasive carcinomas in cold biopsy specimens were 22.2%, 100%, 100%, and 71.4% respectively, respectively and for distinguishing between intramucosal lesions and those invading the submucosa or beyond was 59.7%, 100%, 100%, and 37.6% respectively.The sensitivity, specificity, positive and negative predictive values ​​of the Japanese Group Classification for distinguishing between intramucosal lesions and submucosal invasive carcinomas in cold biopsy were 83.3%, 91.4%, 83.3%, and 91.4% respectively, respectively, and for distinguishing between intramucosal lesions and those invading the submucosa or beyond was 95.1%, 91.4%, 97.9%, and 82.1% respectively. A total of 137 of 144 carcinomas that had invaded the submucosa or beyond and three high-grade intraepithelial neoplasias were diagnosed as “carcinoma” using the Japanese Group Classif ication system. CONCLUSION: The revised Vienna Classifi cation for cold biopsy specimens has high positive predictive value in the diagnosis of colorectal carcinoma invasive to the submucosa or beyond.