title: Seasonal variations do not affect the superiority of fecal immunochemical tests over guaiac tests for colorectal cancer screening.
abstract: The aim of this study was to compare the seasonal variation in performance of a faecal immunochemical test for haemoglobin (FIT) and a guaiac test (gFOBT) for colorectal cancer screening. From June 2009 to May 2011, 18,290 screening participants (50-74 years old) performed OC-SENSOR quantitative FIT (1 sample) and Hemoccult II gFOBT (3 stool samples with 2 spots/sample). Referral for colonoscopy required a minimum of one positive spot (gFOBT), or a positive FIT [cut-off 150 ng haemoglobin/mL buffer (i.e. 30 μg haemoglobin/g feces)]. The performance of tests for detection of advanced neoplasia was compared according to seasons using Receiver Operating Characteristics (ROC) curves, at various FIT cut-off values. The positivity rate of FIT was significantly lower in the summer compared with other seasons (2.3% versus 3.0%, p = 0.03), whilst the positivity rate of gFOBT increased in the autumn (1.8% versus 1.5%, p = 0.11). FIT was clinically more effective than gFOBT over the four season-specific ROC curves. At the cut-off concentration used in the study, the season-specific FIT/gFOBT ratios for true positive rates were: 2.8 (Autumn), 2.5 (Winter), 3.0 (Spring), 3.7 (Summer), and for false positive rates: 1.2 (Autumn), 1.5 (Winter), 1.8 (Spring), 0.9 (Summer). Therefore, in this study with this cut-off concentration and in spite of lower positivity rate in summer, the seasonal variations of performance of OC-SENSOR FIT led to improved gain in specificity in the summer, without a decrease in gain in sensitivity compared with gFOBT.
authors.affiliation: Centre Hospitalier Universitaire (CHU) de Caen, Evaluations et recherches en épidémiologie, Caen; Normandie University, Caen; Université de Caen Basse-Normandie (UCBN), Cancers and Preventions, Caen; INSERM U1086, Cancers and preventions, Caen.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Chausserie
authors.forename: Romuald
authors.initials: R
authors.lastname: Levillain
authors.forename: Josette
authors.initials: J
authors.lastname: Puvinel
authors.forename: Olivier
authors.initials: O
authors.lastname: Ferrand
authors.forename: Angela
authors.initials: A
authors.lastname: Ruiz
authors.forename: Thibaut
authors.initials: T
authors.lastname: Raginel
authors.forename: Olivier
authors.initials: O
authors.lastname: Lantieri
authors.forename: Guy
authors.initials: G
authors.lastname: Launoy
authors.forename: Lydia
authors.initials: L
authors.lastname: Guittet
mesh_terms: D000368:Aged; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer / Q000379:methods; D005243:Feces / Q000737:chemistry*; D005260:Female; D006138:Guaiac; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007120:Immunochemistry / Q000379:methods; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009780:Occult Blood; D012372:ROC Curve; D012621:Seasons; D012680:Sensitivity and Specificity
chemical_list: D006138:Guaiac
keywords: colorectal neoplasms; comparative study; early detection of cancer; immunochemistry/methods; occult blood; sensitivity and specificity