# Effect of a mobile mammography unit on participation and equity in breast cancer screening: a cluster randomised trial in Normandy, France

## TL;DR

A mobile mammography unit increased breast cancer screening participation in France, especially among women in remote and deprived areas.

## Contribution

This is the first RCT showing that mobile mammography units can reduce geographic and social inequities in breast cancer screening.

## Key findings

- The mobile mammography unit increased screening participation by 8.7% compared to the control group.
- Women using the mobile unit were younger and more deprived than those using traditional centers.
- The intervention reduced socioterritorial inequalities in screening participation.

## Abstract

Participation in organised breast cancer screening (OBCS) in France has declined over the past decade. This study evaluated the contribution of mobile mammography units (MMUs) to increasing screening participation through a prospective cluster-randomised controlled trial conducted in France.

This interventional study was conducted among the general population in four departments of the Normandy region. Areas located >15 min from a radiology centre were grouped into clusters and randomly assigned (1:1) to either an intervention or control arm. In total, 320 areas inhabited by 87,449 women aged 50–74 years were included. In the intervention arm, women whose last mammogram was performed at least 22 months earlier received, besides to the usual invitation, an appointment at the MMU sent by the regional screening management structure. The primary outcome was the BCS participation rate. A cluster-adjusted proportion test was used to compare participation between arms.

In the intervention arm, 22,964 women were screened out of the 38,382 invited, yielding a participation rate of 59.8 % vs 51.1 % in the control areas (25,099/49,067). The MMU intervention was associated with a statistically significant increase in participation of 8.7 % (p < 0.0001) compared with the control arm. In the intervention arm, women screened in the MMU tended to be younger and more deprived than those who opted for a radiology centre.

The addition of an MMU to the OBCS programme in France significantly increased participation among women living furthest from radiology centres and can reduce social and geographic inequities.

•Socioterritorial inequalities exist in breast cancer screening participation.•Mobile mammography units (MMUs) are used in various countries for screening.•No RCTs have assessed the effectiveness of MMUs for breast cancer screening.•Using MMUs can increase screening participation in deprived populations.•Using MMUs with proportionate universalism can reduce socioterritorial inequalities.

Socioterritorial inequalities exist in breast cancer screening participation.

Mobile mammography units (MMUs) are used in various countries for screening.

No RCTs have assessed the effectiveness of MMUs for breast cancer screening.

Using MMUs can increase screening participation in deprived populations.

Using MMUs with proportionate universalism can reduce socioterritorial inequalities.