Timing and Risk Factors for a Positive Fecal Immunochemical Test in Subsequent Screening for Colorectal Neoplasms.
BACKGROUND
Following a negative test, the performance of fecal immunochemical testing in the subsequent screening round is rarely reported. It is crucial to allocate resources to participants who are more likely to test positive subsequently following an initial negative result.


OBJECTIVE
To identify risk factors associated with a positive result in subsequent screening.


METHODS
Dataset was composed of consecutive participants who voluntarily underwent fecal tests and colonoscopy in a routine medical examination at the National Taiwan University Hospital between January 2007 and December 2011. Risk factor assessment of positive fecal test in subsequent screening was performed by using the Cox proportional hazards models.


RESULTS
Our cohort consisted of 3783 participants during a 5-year period. In three rounds of subsequent testing, 3783, 1537, and 624 participants underwent fecal tests, respectively; 5.7%, 5.1%, and 3.9% tested positive, respectively, and the positive predictive values were 40.2%, 20.3%, and 20.8%, respectively. Age ≥60 years (adjusted hazard ratio: 1.53, 95% CI: 1.21-1.93) and male gender (1.32, 95% CI: 1.02-1.69) were risk factors; however, an interaction between age and gender was noted. Men had higher risk than women when they were <60 years of age (p = 0.002), while this difference was no longer observed when ≥60 years of age (p = 0.74). The optimal interval of screening timing for participant with baseline negative fecal test was 2 years.


CONCLUSIONS
Following a negative test, older age and male gender are risk factors for a positive result in the subsequent rounds while the gender difference diminishes with age. Biennial screening is sufficient following a negative fecal test.
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Integrated Diagnostics and Therapeutics, National Taiwan University Hospital, Taipei, Taiwan.
Tsung-Hsien
TH
Chiang
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Yi-Chia
YC
Lee
Department of Health Care Management, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
Wan-Chung
WC
Liao
Department of Health Care Management, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
Jui-Hung
JH
Chung
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Han-Mo
HM
Chiu
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Chia-Hung
CH
Tu
Department of Health Care Management, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan.
Su-Chiu
SC
Chen
Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Primary Care Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Ming-Shiang
MS
Wu
D000367:Age Factors; D014408:Biomarkers, Tumor / Q000032:analysis; D015331:Cohort Studies; D003106:Colon / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D055088:Early Detection of Cancer; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D007120:Immunochemistry; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012007:Rectum / Q000473:pathology*; D012307:Risk Factors; D012737:Sex Factors; D013624:Taiwan / Q000453:epidemiology
D014408:Biomarkers, Tumor