title: Characteristics of colorectal tumours in asymptomatic patients with negative immunochemical faecal occult blood test results.
abstract: The immunochemical faecal occult blood test (iFOBT) is a simple, non-invasive colorectal cancer (CRC) screening method for reducing CRC-related mortality. However, the sensitivity of iFOBT is imperfect and certain colonic neoplasms that require removal may be missed. The aim of this study was to investigate the incidence and characteristics of CRC in asymptomatic, iFOBT-negative patients who underwent opportunistic screening. A total of 919 subclinical patients (276 iFOBT-positive and 643 iFOBT-negative) in the health screening program of our hospital underwent total colonoscopy (TCS) within 2 years after iFOBT. The patients were divided into an iFOBT-positive and an iFOBT-negative group and the TCS findings were compared between the two groups. Although the incidence of advanced neoplasia (CRC, high-grade dysplasia, adenoma sized ≥10 mm and tubulovillous adenoma) was significantly higher in the iFOBT-positive group, these lesions were also found in 6.3% of iFOBT-negative patients. The lesions tended to be proximally located and non-protruding. In conclusion, screening with iFOBT remains clinically significant. However, colonoscopy is indispensable for reducing the incidence and mortality of CRC.
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Wakamura
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Shin-Ei
authors.initials: SE
authors.lastname: Kudo
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Miyachi
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Kodama
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Seiko
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Ogawa
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Kouyama
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Kataoka
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kato
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Katsuro
authors.initials: K
authors.lastname: Ichimasa
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Misawa
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Toyoki
authors.initials: T
authors.lastname: Kudo
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Takemasa
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Ishida
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa 224-8503, Japan ; Department of Internal Medicine, School of Life Dentistry, Nippon Dental University, Niigata, Niigata 951-8580, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Ohkoshi
keywords: advanced adenoma; advanced neoplasia; asymptomatic patient; colonoscopy; colorectal cancer screening; immunochemical faecal occult blood test; opportunistic screening