Dr Nea Malila and colleagues from Finnland report on the sensitivities of the fecal occult blood test, screening episode, and screening program for colorectal cancer.
The research team evaluated the benefits of applying a randomized design at the implementation phase of a new public health policy.
The team assessed 106,000 adults randomized to screening or control arms.
In total, 52,998 adults aged 60 to 64 in the screening arm received fecal occult blood test kits.
|The sensitivity of the fecal occult blood test was 55%|
|British Medical Journal|
The team’s main outcome measures included test, episode, and program sensitivities estimated by the incidence method, corrected for selective attendance and overdiagnosis.
The researchers found that the response for screening was high overall, and significantly better in women than in men.
The incidence of cancer in the controls was somewhat higher in men than in women, at 103 vs 93 per 100,000 person years.
This gender difference was not true for interval cancers.
The sensitivity of the fecal occult blood test was 55%.
Only a few interval cancers were detected among those with positive test results, hence the episode sensitivity of 51% was close to the test sensitivity.
At the population level the sensitivity of the program was 38%.
Dr Malila’s team concluded, “Although relatively low, the sensitivity of screening for colorectal cancer with the fecal occult blood test in Finland was adequate.”
“An experimental design is a prerequisite for evaluation of such a screening program because the effectiveness of preventing deaths is likely to be small and results may otherwise remain inconclusive.”
“Thus, screening for colorectal cancer using any primary test modality should be launched in a public health program with randomization of the target population at the implementation phase.”