Like in other industrialised countries, in Finland colorectal cancer is an important cause of premature death. The disease can be detected in symptomless persons at an early, localised stage, when it often is possible to give curative treatment. Screening aims at reducing mortality. Screening for colorectal cancer is being considered in many European countries, but no country at present offers screening for its population. Active follow-up of risk groups takes place in several countries, including Finland; the extent of these programmes varies.
Many alternative methods are available for screening. Detection of occult blood in stools is the most common primary test. If blood is detected, the next examination can be either endoscopy or radiography of the colon. Colonoscopy has been studied also as the primary method for screening. The willingness of the Finnish population to participate in screening for colorectal cancer is inadequately known and it is difficult to estimate, as this screening differs in many ways from other screening programmes and tests currently in use.
In addition to expected results, all screening programmes also have negative effects. Common problems in cancer screening are that some cancers are not detected (false negatives), and that cancer is suspected in some participants who actually do not have the disease (false positives). Although the number of false results is usually small, they cause considerable cost and inconvenience, which need to be taken into account when screening is considered. A full cost-effectiveness evaluation of cancer screening must also include an estimate of the cost of treating the cancers detected. The treatment of colorectal and other cancers is constantly changing, and the changes also affect survival. In this limited evaluation, the cost of treatment could not be included at all.
The introduction of any screening is thus coloured with considerable insecurity. Before a decision about starting a national screening programme for colorectal cancer is made, it seems necessary to do a pilot study. This would provide the missing data on the practical conditions as well as the costs and effects of implementing screening on a smaller scale. Thus it would be possible to diminish the insecurity associated with the creation of a new, institutionalised screening programme for colorectal cancer.