שאלה משלב א׳ בבריאות הציבור · מועד 2024 (Sep), שאלה 84

Correct: A — an increase in one-year survival among patients with pancreatic cancer. In the first year of a screening programme for an untreatable cancer, the one effect that is certain is lead time: tumours are diagnosed earlier in their natural history, so survival measured from the date of diagnosis lengthens even though no death is postponed. Incidence (option B) will *rise* in the screening year, not fall, because prevalent undetected cancers are pulled forward into that year's diagnoses; prevalence (option C) will also rise, since people now live longer as diagnosed cases; and there is no reason for the incidence of pancreatitis (option D) to change. The design implication is that a screening programme must be evaluated by cause-specific mortality in the whole invited population.

מקור: גורדיס, ch.18