title: The Optimal Cut-Off Level of The Fecal Immunochemical Test For Colorectal Cancer Screening in a Country with Limited Colonoscopy Resources: A Multi-Center Study from Thailand
abstract: Background: Selecting the cut-off point for the fecal immunochemical test (FIT) for colorectal cancer (CRC)
  screening programs is of prime importance. The balance between the test performance for detecting advanced neoplasia
  and the available colonoscopy resources should be considered. We aimed to identify the optimal cut-off of FIT for
  advanced neoplasia in order to minimize colonoscopy burden. Methods: We conducted a multi-center study in 6
  hospitals from diverse regions of Thailand. Asymptomatic participants, aged 50-75 years, were tested with one-time
  quantitative FIT (OC-SENSOR, Eiken Chemical Co.,Ltd., Tokyo, Japan) and all participants underwent colonoscopy.
  We assessed test performance in detecting advanced neoplasia (advanced adenoma and CRC) and measured the burden
  of colonoscopy with different cut-offs [25 (FIT25), 50 (FIT50), 100 (FIT100), 150 (FIT150), and 200 (FIT200)ng/ml].
  Results: Among 1,479 participants, advanced neoplasia and CRC were found in 137 (9.3%) and 14 (0.9%), respectively.
  From FIT25 to FIT200, the positivity rate decreased from 18% to 4.9%. For advanced neoplasia, an increased cut-off
  decreased sensitivity from 42.3% to 16.8% but increased specificity from 84.2% to 96.3%. The increased cut-off
  increased the positive predictive value (PPV) from 21.5% to 31.5%. However, all cut-off points provided a high negative
  predictive value (NPV) (>90%). For CRC, the miss rate for FIT25 to FIT 150 was the same (n=3, 21%), whereas that
  with FIT200 increased to 35% (n=5). Conclusions: In a country with limited-colonoscopy resources, using FIT150
  may be preferred because it offers both high PPV and NPV for advanced neoplasia detection. It could also decrease
  colonoscopy workload, while maintaining a CRC miss rate similar to those with lower cut-offs.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn  University and King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok,  Thailand. Email: ercp@live.com
authors.forename: Satimai
authors.initials: S
authors.lastname: Aniwan
authors.forename: Thawee
authors.initials: T
authors.lastname: Ratanachu Ek
authors.forename: Supot
authors.initials: S
authors.lastname: Pongprasobchai
authors.forename: Julajak
authors.initials: J
authors.lastname: Limsrivilai
authors.forename: Ong Ard
authors.initials: OA
authors.lastname: Praisontarangkul
authors.forename: Pises
authors.initials: P
authors.lastname: Pisespongsa
authors.forename: Pisaln
authors.initials: P
authors.lastname: Mairiang
authors.forename: Apichat
authors.initials: A
authors.lastname: Sangchan
authors.forename: Jaksin
authors.initials: J
authors.lastname: Sottisuporn
authors.forename: Naruemon
authors.initials: N
authors.lastname: Wisedopas
authors.forename: Pinit
authors.initials: P
authors.lastname: Kullavanijaya
authors.forename: Rungsun
authors.initials: R
authors.lastname: Rerknimitr
keywords: Fecal occult blood test; colorectal cancer screening; colonoscopy