Dr Sei Lee and colleagues performed a meta-analysis of survival data from population based, randomized controlled trials comparing populations screened and not screened for breast or colorectal cancer.
The team identified trials as high quality by reviews from the Cochrane Collaboration and United States Preventive Services Task Force.
The trials were undertaken in the United States, Denmark, United Kingdom, and Sweden in screened patients older than 40 years.
The research team's primary outcome measures included time to death from breast or colorectal cancer in screened and control populations.
The team assessed fecal occult blood testing for colorectal cancer screening, mammography for breast cancer screening.
|It took 10 years to prevent 1 death from colorectal cancer for 1000 patients screened|
|British Medical Journal|
The team included 5 and 4 eligible trials of breast and colorectal cancer screening, respectively.
For breast cancer screening, 3 years passed before one death from breast cancer was prevented for every 5000 women screened.
The researchers observed that on average across included studies, it took 11 years before one death from breast cancer was prevented for 1000 women screened.
For colorectal cancer screening, 5 years passed before 1 death from colorectal cancer was prevented for 5000 patients screened.
The team of doctors noted that on average it took 10 years before 1 death from colorectal cancer was prevented for 1000 patients screened.
Dr Lee's team commented "Our results suggest that screening for breast and colorectal cancer is most appropriate for patients with a life expectancy greater than 10 years."
"Incorporating time lag estimates into screening guidelines would encourage a more explicit consideration of the risks and benefits of screening for breast and colorectal cancer."