ORLANDO – Colonoscopy with or without fecal occult blood testing is associated with lower overall mortality risk in individuals with increased baseline colorectal cancer risk, findings from a large prospective cohort study suggest.
Overall mortality was 33.2% in 2,123 Veterans Administration patients aged 21-89 years who were followed for up to 16 years as part of the study. Deceased patients, compared with those still living at the end of the study period, had significantly lower odds of having undergone colonoscopy alone (18.5% vs. 23%) or colonoscopy plus fecal occult blood testing (17.4% vs. 23.9%), and significantly greater odds of having undergone neither screening modality (41.4% vs. 28%), Dr. Martin Tobi reported at the annual Digestive Disease Week.
The use of fecal occult blood testing (FOBT) alone was not associated with overall mortality; 25% and 22% of the deceased and living patients, respectively, underwent FOBT alone, said Dr. Tobi of the University of Pennsylvania, Philadelphia.
Study participants were adults seen at the outpatient primary care clinics of a VA hospital between 1995 and 2012. Some had symptoms and some did not – this was not a screening population, Dr. Tobi noted.
Dr. Martin Tobi
The subjects were followed for a mean of 8 years. Risk for colorectal cancer at baseline was assessed using a risk questionnaire and based on past neoplasia, chronic inflammatory bowel disease, symptomatology, and family history. Mortality and use of FOBT and colonoscopy were determined by a manual medical records review.
The impact of colonoscopy and FOBT on overall mortality associated with colorectal cancer has been unclear, and although large-scale randomized trials to evaluate the relationships are ongoing, definitive results are more than a decade away, Dr. Tobi said.
Though limited by missing data in a substantial number of cases, the current findings from a large VA population suggest there is indeed a relationship between colonoscopy with or without FOBT and overall mortality.
"Further analyses are needed to determine whether a true protective effect of colonoscopy is attributable to a causal relationship or due to a confounding one – mainly a healthy user effect," he concluded.
The Veterans Health Administration provided funding for this study. Dr. Tobi reported having no disclosures.