Using physician-linked mailed invitations in an organised colorectal cancer screening programme: effectiveness and factors associated with response.

Objectives: A central tenet of organised cancer screening is that all persons in a target population are invited. The aims of this study were to identify participant and physician factors associated with response to mailed physician-linked invitations (study 1) and to evaluate their effectiveness in an organised colorectal cancer (CRC) screening programme (study 2).
Design and Setting: 2 studies (study 1-cohort design and study 2-matched cohort design, comprising study 1 participants and a matched control group) were conducted in the context of Ontario's organised province-wide CRC screening programme.
Participants: 102 family physicians and 11 302 associated eligible patients from a technical evaluation ('the Pilot') of large-scale mailed invitations for CRC screening were included. Matched controls were randomly selected using propensity scores from among eligible patients associated with family physicians in similar practice types as the Pilot physicians.
Intervention: Physician-linked mailed invitation to have CRC screening.
Outcomes: Uptake of faecal occult blood test (FOBT) within 6 months of mailed invitation (primary) and uptake of FOBT or colonoscopy within 6 months of mailed invitation (secondary).
Results: Factors significantly associated with uptake of FOBT included prior FOBT use, older participant age, greater participant comorbidity and having a female physician. In the matched analysis, Pilot participants were more likely to complete an FOBT (22% vs 8%, p<0.0001) or an FOBT or colonoscopy (25% vs 11%, p<0.0001) within 6 months of mailed invitation than matched controls. The number needed to invite to screen one additional person was 7.
Conclusions: Centralised large-scale mailing of physician-linked invitations is feasible and effective in the context of organised CRC screening.