Comparing risks and benefits of colorectal cancer screening in elderly patients.

BACKGROUND & AIMS: In patients with limited life expectancy, the risks of colorectal cancer screening may outweigh the benefits. The aim of this study was to quantify risks and benefits of different screening strategies in elderly patients with varying life expectancies.

METHODS

We examined risks and benefits of screening in patients aged 70-94 years with differing health status using 3 strategies: annual fecal occult blood tests, flexible sigmoidoscopy every 5 years, or colonoscopy every 10 years. We compared the number needed to screen to prevent one cancer-related death and the number needed to encounter one screening-related complication for different strategies.

RESULTS

The potential benefit from screening varied widely with age, life expectancy, and screening modality. One cancer-related death would be prevented by screening 42 healthy men aged 70-74 years with colonoscopy, 178 healthy women aged 70-74 years with fecal occult blood tests, 431 women aged 75-79 years in poor health with colonoscopy, or 945 men aged 80-84 years in average health with fecal occult blood tests. Colonoscopy screening had the greatest benefit but the highest risk of complications. The potential for screening-related complications was greater than estimated benefit in some population subgroups aged 70 years and older. At all ages and life expectancies, the potential reduction in mortality from screening outweighed the risk of colonoscopy-related death.

CONCLUSIONS

The potential benefits and risks of screening vary in elderly patients of different life expectancies. For any individual patient, the potential for harm from screening must be weighed against the likelihood of benefit, especially with shorter life expectancy.