Breast Cancer Screening in Women With Multiple Sclerosis: A Mixed-Methods Study

Background There is little information on breast cancer screening (BCS) practices in women with multiple sclerosis (WwMS). Objective To assess and compare BCS rates in WwMS and in the general population and identify barriers and facilitators. Methods In a 2012-2020 cohort study, we identified 47,166 WwMS without a history of cancer and matched them (up to 1:4) to 184,124 controls from the French national medico-administrative database. Mammography rates were compared according to age, city-level socio-economic status, period, and DMT use. We used logistic and negative binomial models to identify factors associated with BCS adherence in WwMS. We also carried out semistructured interviews with 20 WwMS and analyzed them using the empirically inductive method. Results Compared with controls, fewer WwMS underwent BCS at least once (69.9% vs. 76.7%, p < 0.001) and had a lower biennial mammography rate (0.55 vs. 0.63; p < 0.001). Rate differences increased with age. Once stratified on DMT, age-standardized rates only differed in the non-treated group (0.51 vs. 0.64; p < 0.001). Factors associated with lower mammography rates in WwMS were city-level socio-economic status (mostdeprived vs. least deprived; IRR 0.88 95% CI [0.86-0.91]), long MS duration (16-25 years: 0.91 [0.89-0.94]; ref: <= 5) and hospitalization (MS-related: 0.85 [0.82-0.88]; non-MS-related: 0.92 [0.89-0.94]). However, DMT use was associated with higher mammography rates (high efficacy: 1.17 [1.14-1.21]; moderate efficacy: 1.18 [1.16-1.20]). Barriers were physical disability and feeling of excessive medicalization. Facilitators were disability-accessible care and perception of BCS as a routine procedure. Conclusion BCS among WwMS is suboptimal, especially among those not treated by DMT, and needs to be improved.