A randomized controlled trial comparing three invitation strategies in a breast cancer screening program

The objective of this study was to compare the response received by a population-based breast cancer screening program, according to three different invitation strategies: letters sent by mail from the program (program group), letters sent by mail from the Primary Health Care Team (PHT group), and direct contact through a trained professional (direct contact group).

We used a cluster-randomized controlled trial with assignment to invitation group using home address. Nine hundred eighty-six women of Barcelona (Spain), ages 50 to 64 years, were invited to participate in the program. The main outcome used was the response rate after the first invitation.

Five hundred sixty-four women accepted the invitation (57.2%). The highest response rate was achieved in the direct contact group (63.5%), followed by the PHT group (55.6%), the program group being the one that attained the lowest response rate (52.1%). The direct contact group had a higher probability of participating than the PHT group (RR = 1.14, P = 0.037) or the program group (RR = 1.22, P = 0.003). The response rate in the direct contact group was 72.1% when the letter was received by the subject herself. The increase in response occurred particularly among women of lower educational level.

Inviting women to participate in a breast cancer screening program through direct contact by trained personnel increased participation rate compared with mailed-letter methods. The positive effect appeared restricted to women with lower educational levels.