Minimal benefit of earlier-than-recommended repeat colonoscopy among US Medicare enrollees following a negative colonoscopy

Long-Term Colorectal Cancer Incidence After Negative Colonoscopy in the State of Utah: The Effect of Family History

OBJECTIVES

Colonoscopy is widely recommended for colorectal cancer (CRC) screening, but evidence to guide the optimal frequency of repeat screening examination is limited. We examined the duration and magnitude of the risk of developing CRC, following a negative colonoscopy in those at average risk and those with a first-degree family history of CRC.

METHODS

A cohort of Utah residents aged 50-80 years who had a negative colonoscopy between 1 January 2001 and 31 December 2011 was identified using the Utah Population Database. Patients were followed from the time of the index colonoscopy until diagnosis of CRC, death, migration out of state, repeat colonoscopy, or end of the study period. CRC incidence after the index colonoscopy was compared with that of the state population by standardized incidence ratios (SIRs).

RESULTS

A cohort of 131,349 individuals at average risk with a negative colonoscopy was identified. Compared with the state population, a negative colonoscopy was associated with SIRs of 0.15 (95% confidence interval (CI): 0.08-0.23) at 1 year, 0.26 (95% CI: 0.19-0.32) at 2-5 years, 0.33 (95% CI: 0.22-0.43) at 5-6 years, and 0.60 (95% CI: 0.44-0.76) at 7-10 years for CRC following the index colonoscopy. In a secondary analysis involving only patients with a first-degree relative with CRC, patients had a significantly lower incidence of CRC only for the first 5 years of follow-up (SIR 0.39, 95% CI: 013-0.64). There was also a difference in the risk of proximal (SIR 0.72, 95% CI: 0.45-0.98) and distal (SIR 0.51, 95% CI: 0.30-0.72) colon cancers at 7-10 years following a negative colonoscopy.

CONCLUSIONS

The risk of developing CRC remains decreased for at least 10 years following the performance of a negative colonoscopy. However, the lower incidence of CRC in those with a family history of CRC differed in magnitude and timing being limited primarily to the first 5 years of follow-up and of lesser magnitude than that in the overall cohort.

Colonoscopy in Colorectal Cancer Screening: Current Aspects

Colonoscopy represents a very important diagnostic modality for screening for colorectal cancer, because it has the ability to both detect and effectively remove pro-malignant and malignant lesions. It is recommended by almost all international and national gastroenterology and cancer societies, as an initial screening modality or, following a positive fecal occult blood test, to be performed every 10 years in individuals of average risk starting from the age of 50. However, a significant problem is the so-called post-screening (interval) polyps and cancers found some years after the index colonoscopy. In order to reduce the rate of interval cancers it is extremely necessary to optimize the quality and effectiveness of colonoscopy. Bowel preparation is of paramount importance for both accurate diagnosis and subsequent treatment of lesions found on colonoscopy. The quality of bowel preparation could be significantly improved by splitting the dose regimens, a strategy that has been shown to be superior to single-dose regimen. A good endoscopic technique and optimal withdrawal time offering adequate time for inspection, would further optimize the rate of cecal intubation and the number of lesions detected. During the last years, sophisticated devices have been introduced that would further facilitate cecal intubation. The percentage of total colonoscopies is now super-passing the level of 95 % allowing the adenoma detection rate to be greater than the suggestive level of 25 % in men and 15 % in women. This review aims to provide the reader with the current knowledge concerning indications, usefulness, limitations and future perspectives of this probably most important screening technique for colorectal cancer available today.