Public understanding of the purpose of cancer screening: A population-based survey.

Objectives: In examining informed choice in cancer screening, we investigated public awareness that some screening programmes aim to prevent cancer, while others seek to detect cancer at an early stage. Methods: A population-based survey of adults aged 50-70 in England (n = 1433), including data on demographic characteristics and screening experience. Participants were asked to select the main purpose of cervical, breast, and colorectal cancer screening (both faecal occult blood testing and flexible sigmoidoscopy). Results: Across all four screening programmes, most people thought the main aim was to catch cancer early (71-78%). Only 18 and 14% knew that cervical screening and flexible sigmoidoscopy, respectively, are primarily preventive. Knowledge of the preventive aspect of these two programmes was low across the board, with few demographic patterns. By contrast, 78 and 73% of the sample were aware that breast screening and the faecal occult blood test, respectively, predominantly aim to detect cancer early. For these programmes, accurate knowledge was socially graded, lower in ethnic minority groups, and positively associated with previous participation in the programmes. Conclusions: Our findings suggest that although awareness of the purpose of early detection screening is high, awareness that screening can prevent cancer is low across all demographic groups. Understanding the purpose of screening is a key aspect of informed choice but despite current communication strategies highlighting these differences, people do not seem to have a nuanced understanding of these differing aims. Our findings may be indicative of a broader public scepticism about the preventability of cancer.