Breast cancer screening enables early detection of breast cancer which leads to a reduction in mortality.1,2 The Quebec breast cancer screening program began in 1998 and offers women aged 50-69 a biennial screening mammography. 3 Since 2002, three mammography mobile units were progressively added to the program. The program relies on two motorized units and a portable unit transported by plane or boat that extends screening services to regions not accessible by land. In the present study, we use the term "mobile units" to refer to both (motorized and portable) types of mammography units. The purpose of these units is to provide services to regions not covered by fixed centres. In addition, they can provide temporary relief to fixed centres that have insufficient resources to ensure timely breast screening.Mobile units have been added to screening programs in various countries to increase geographical accessibility to breast cancer screening. 4 Studies have shown that mobile units are effective at improving the participation rate, 5-7 that mobile units can decrease barriers to screening for hard-to-reach populations 8 and that educational interventions associated with mobile unit visits can increase adherence.9 However, mobile units have different operating practices when compared to stationary (fixed) centres in terms of personnel, work conditions and environment. Moreover, screening in mobile units may require ongoing calibration of instruments, and where analogue units are used, films cannot be developed onsite. These differences could have an impact on screening outcomes but there are few studies comparing the performance of mobile units to fixed sites. 10,11 These studies focussed primarily on comparing costs and other elements (price, access, quality assurance). In some studies, screening results for mobile units were reported but were not compared to fixed centres. 8,[12][13][14] The aims of this study were to evaluate the contribution of mobile mammography units to participation rate, and to compare screening performance between mobile units and fixed centres in the organized mammography screening program of Quebec, Canada.
METHODS
Population and dataAll eligible women residing in the province, aged 50-69 years, are invited to participate in the Quebec breast cancer screening program. Each participant is asked to sign a written consent form to allow the collection of personal characteristics and screening information. Over the study period, 98% of participants provided written consent. ABSTRACT BACKGROUND: The aims of this study were to evaluate the contribution of mobile mammography units to participation rate and to compare their performance to fixed screening centres within the organized mammography screening program of Quebec, Canada.