It's not purely a screening issue -- there are no mandatory screenings for teenagers, so any screenings done would be in response to showing symptoms. That said

It's not purely a screening issue -- there are no mandatory screenings for teenagers, so any screenings done would be in response to showing symptoms. That said, as awareness of incidence of youth colorectal cancer becomes more widespread, it is more likely to be seen as a possibility, and thus increase the number of tests run. As always there are rabbit/turtle/bird situations; it's impossible to say how many of these early detections are of slow-growing benign conditions that left untreated would never pose a threat to quality of life or morbidity or mortality. But because these tests are not done by default, but only in response to some reported symptoms, it is more likely that there is an actual increase in incidence. It does not appear that this is yet a published study, which might give more data on the prevalence of testing that might in turn give an idea of how much the screening effect contributes.