Risk for colorectal cancer in elderly persons and possible methodologies for their screening

Most colorectal cancer (CRC) screening guidelines recommend average-risk screening up to the age of 75 years. However, increasing life span and incidence of proximal CRC could require changes to the age guidelines and adapting screening methodology for the elderly persons. Therefore, we reviewed our CRC epidemiology, international screening age-guidelines, and screening tests for the elderly persons and presented our long-term results of colonoscopy and semi-quantitated immunochemical fecal occult blood tests (I-FOBTs) in individuals that are 75 years or more.

We examined the Israel National Cancer Registry (INCR) data to assess the risk of CRC in individuals aged 75 years or more. We re-examined files of patients aged 75 years or more, who underwent both colonoscopy and three I-FOBTs, and followed them through the INCR to identify new cases of CRC.

Nationwide, during 2005 and 2007, 41.3% of all CRCs occurred in individuals aged 75 years or more. Both I-FOBT and colonoscopy were performed on 271 individuals (mean age: 78.5 years, standard deviation: 3.1). Both initial colonoscopy and I-FOBT of at least 50 ngHb/ml buffer in either of the first two tests identified six patients with CRC; INCR registered another stage 1 rectal CRC within 1 year. Therefore, the initial sensitivity to CRC of either test was 85.7% (95% confidence interval: 59.8 and 112), valid during a mean of 44.3 months and a standard deviation of 13.4 at INCR follow-up; 14 of 27 advanced adenomatous polyps were identified by I-FOBT, giving a sensitivity of 58.8% (95% confidence interval: 42.3 and 75.4) for CRC or advanced adenomatous polyps.

Recently, 41.3% of our CRCs occurred in individuals aged 75 years or more, diagnosed clinically and not by screening. I-FOBT and initial colonoscopic CRC sensitivity were similar, both having false-negative results. Screening age guidelines need reconsideration; our initial results show that semi-quantitated I-FOBT screening is feasible but needs large-scale evaluation in 'healthy' elderly persons.