Screening uptake

Why it is the number that matters. A screening programme's effect on a population is its effect on those screened multiplied by the share who take part. NordICC is the clearest illustration: a single invitation to colonoscopy cut the 10-year risk of colorectal cancer by 18 percent, but only 42 percent of those invited attended, and analyses of the people actually screened estimated a 35 to 41 percent reduction (Bretthauer 2022). The Nottingham faecal occult blood trial saw 59.6 percent complete at least one screen, 38.2 percent complete every test offered and 40.4 percent complete none; 44.8 percent of the cancers in the screening arm arose in people who never took a test (Hardcastle 1996).

The gradient. England's screening standards set an acceptable uptake of 62 percent and an achievable level of 73 to 76 percent for ages 60 to 74, with levels for the newly invited 50 to 59 group not yet set (GOV.UK). In the first 14 months of the English bowel scope programme, uptake was 43.1 percent overall but ranged from 33 percent in the most deprived fifth of areas to 53 percent in the least, with lower uptake in the most ethnically diverse areas and a small advantage for out-of-hours appointments (J Med Screen 2016). Deprivation shows in the outcome too: five-year bowel cancer survival in England is 55 percent in the most deprived group and 62.9 percent in the least (Cancer Research UK).

What moves it. Postal tests that reach people at home, a single simple sample, free return postage, GP endorsement of the invitation, reminders and translated materials are the levers organised programmes use; England's move from the guaiac test to the faecal immunochemical test in 2019 improved uptake as well as accuracy because one sample replaced six.