Occult-blood screening for colorectal carcinoma: the yield and the costs.

The potential benefits and risks associated with Hemoccult screening have been reviewed in two companion papers. This final article assesses two major determinants of the overall "disease yield" of occult-blood screening, as well as the economic costs entailed by the maneuver. First, asymptomatic polyps detected and treated by such screening are more properly considered "false" positives than "true" positives--the benefits of their aggressive diagnosis and extirpation in the general population being much less established than the risks. Secondly, the ongoing detection rate for colorectal carcinoma on subsequent (e.g., annual) screenings of a population already screened will be substantially less than the initial screening yield; yet, the risks of confirmatory diagnostic procedures remain high. Lastly, there are many hidden costs to occult-blood screening that have generally not been recognized. Therefore, the use of Hemoccult screening as a routine health maintenance maneuver cannot yet be justified for any age-group.