Breast Cancer Screening and Impact on Cancer Outcomes in Kuwait

The Kuwait National Mammography Screening Programme (KNMSP) was launched in 2014 to address the increasing burden of breast cancer (BC) among women. Screening uptake seems however to remain low. The overarching aim of this thesis is to provide a comprehensive picture of the BC screening situation in Kuwait to improve screening strategies, reduce advanced BC stages, and improve BC outcomes for women in Kuwait.

To achieve that, population-based cancer registry data were linked to KNMSP screening data and other mammography data from governmental hospital services. Other data sources were used to provide information on socio-demographic characteristics and vital status of women. The first specific aim was to estimate the BC screening uptake, overall and according to associated factors, using a generalised linear model with a negative binomial distribution. In the second specific aim, a multinomial logistic regression was applied to estimate the impact of screening engagement on stage at diagnosis among Kuwaiti and non-Kuwaiti women. The complete-case analyses were complemented with multiple imputation and sensitivity analyses. Finally, net survival by BC screening engagement was estimated using the consistent non-parametric Pohar-Perme estimator.

The first study highlights persistently low BC screening uptakes among both Kuwaiti and non-Kuwaiti women. Even though uptake varies according to socio-demographic and geographic factors, the overall screening uptakes are too low to have any significant impact at population level.

The second study finds a strong association between engagement in screening and lower odds of advanced-stage BC diagnosis in both Kuwaiti and non-Kuwaiti women.

The third study shows the association of higher screening engagement with improved survival outcomes among BC patients, even after correcting for potential lead-time bias.

Major changes to the KNMSP are urgently needed if it is to have a significant impact on BC survival. Targeted awareness campaigns and invited screenings are key to improving participation in the BC screening programme