Each year in France, breast cancer affects about 48,000 women and is the first cause of cancer death in women with 11,900 deaths estimated.

Since 2004, there is a national organized breast cancer screening (OBCS) programme for asymptomatic women aged 50-74 and with a medium-risk. Every two years, the local cancer screening department sends a personalized invitation mail to eligible women to perform a mammogram and a breast clinical examination. One to two reminder mails are sent to women who have not done the screening after an initial invitation. Despite this programme, almost 47% of women in France do not participate to organized breast cancer screening.

The Short Message Service (SMS) is an innovative communication tool in the field of health, immediate, reliable delivery, low cost and ecological. The use of SMS could be an innovative, low-cost, personalized and ecological way to support the OBCS invitation strategy.

The overall objective of this study is to preserve or even better increase participation in organized breast cancer screening while decreasing the associated costs by including SMS in our screening invitation procedure.

Two SMS interventions will be tested which will correspond to different phases of the OBCS invitation procedure. This sequence of interventions leads us to perform three interlinked trials: a trial of superiority for the first phase (intervention 1: sending an SMS a few days before the initial mail invitation), then two non-inferiority trials for the second phase ( two trials=one for each context of phase 1 _ intervention 2: sending an SMS in place of the first postal reminder).

Each year in France, breast cancer affects about 48,000 women and is the first cause of cancer death in women with 11,900 deaths estimated.

Since 2004, there is a national organized breast cancer screening (OBCS) programme for asymptomatic women aged 50-74 and with a medium-risk. Every two years, the local cancer screening department sends a personalized invitation mail to eligible women to perform a mammogram and a breast clinical examination. One to two reminder mails are sent to women who have not done the screening after an initial invitation. Despite this programme, almost 47% of women in France do not participate to organized breast cancer screening.

The Short Message Service (SMS) is an innovative communication tool in the field of health, immediate, reliable delivery, low cost and ecological. The use of SMS could be an innovative, low-cost, personalized and ecological way to support the OBCS invitation strategy.

In databases, there is currently about 10 to 15% of the women with a mobile phone number registered in the target population.

This project will be carried out throughout the Region "Centre-Val de Loire" with six local cancer screening departments The overall objective of this study is to preserve or even better increase participation in organized breast cancer screening while decreasing the associated costs by including SMS in our screening invitation procedure.

Two SMS interventions will be tested which will correspond to different phases of the OBCS invitation procedure. This sequence of interventions leads us to perform three interlinked trials: a trial of superiority for the first phase (intervention 1: sending an SMS a few days before the initial mail invitation), then two non-inferiority trials for the second phase (intervention 2: sending an SMS in place of the first postal reminder).

Justification of methodological choices

1. st phase: Addition of the intervention "sending an SMS" (and the associated cost) to what is currently done (versus classical intervention). To be of interest, the tested intervention, the sending of an SMS few days before the initial mail invitation, should allow to significantly increase participation in OBCS (here superiority trial).
2. nd phase: This phase will involve women who have had or not the phase 1 intervention and who have not yet participated to the OBCS. Since the contexts in phase 1 are different, a trial for each one must be carry out. In this second phase, the conventional intervention (sending reminder mail 1) will be compare to a cheaper one (sending reminder 1 by SMS). The new strategy will prove interesting if it is not inferior in terms of participation to the OBCS. The analysis of this non-inferiority will be carried out for each context of phase 1 (invitation mail alone OR SMS then invitation mail).

The 4 groups of the study are the followings:

• Group 1 (usual procedure): at least an invitation mail and then one or two reminder by mail if necessary.
• Group 2 : Invitation by mail then reminder 1 by SMS if necessary then reminder 2 by mail if necessary
• Group 3 : One SMS a few days before the Invitation by mail and then one or two reminder(s) by mail if necessary
• Group 4 : One SMS a few days before the Invitation by mail then reminder 1 by SMS if necessary then reminder 2 by mail if necessary

Inclusion Criteria:

• eligible to the organized breast cancer screening
• residing in the region of Centre-Val de Loire (France)
• Phone number registered in data bases of one of the 6 local cancer screening departments of the region of Centre-Val de Loire (France)

Exclusion Criteria:

• none