Kathleen England Neville Calleja 20th October 2017 An ecological analysis of breast cancer mortality and the impact of screening   Kathleen England Neville Calleja 20th October 2017 #PHSymposium17

Introduction Breast cancer is the leading cause of cancer incidence and mortality in females in Malta. On average 321 new cases of breast cancer are diagnosed each year and 80 die from it (3 year average 2013-2015). The National Breast Screening programme was introduced in Malta in October 2009 and started by targeting women in the age group 50-60 years. #PHSymposium17

Incidence and mortality from breast cancer in Malta Source: National Cancer Registry and National Mortality Registry #PHSymposium17

Trends in breast cancer mortality in Malta Source: HFA DB, National Mortality Registry #PHSymposium17

National Breast Screening Programme Source: National Health Screening Services, Malta #PHSymposium17

Breast screening in Malta Source: European Health Interview Surveys 2008 and 2014 #PHSymposium17

Analysis conducted Period under study: 2004-2016. Deaths from breast cancer by single years of age from the National Mortality Registry and age specific mid-populations from the National Statistics Office. These were mapped as to whether screening was in place in the different ages (year 1 of screening was not included as screened). Trends in age specific mortality rates from breast cancer were first analysed. Trends in national breast-cancer mortality by calendar year, taking into account the phased implementation of the screening programme was then undertaken using Poisson Regression. #PHSymposium17

Analysis of Breast Screening programme by age Analysis conducted Analysis of Breast Screening programme by age 2010   60 59 58 2011 61 57 56 2012 62 55 54 2013 63 53 52 2014 64 51 50 2015 65 2016 66 #PHSymposium17

Results: Age Specific Mortality Rates from Breast Cancer #PHSymposium17

Results from Poisson Regression Variable Risk ratio P value 95% CI Age (+1yr) 1.050 <0.001 (1.045; 1.055) Year (+1yr) 1.063 1.082) Screening 0.597 (0.464; 0.768) #PHSymposium17

Discussion Our study showed a positive association between the start of the national screening programme and a reduction in mortality in those age groups exposed to screening. Whilst an overall reduction of 40% was observed in age groups screened, the contribution of screening and that of improved management and treatment cannot be well apportioned. Studies from international literature report reduction in mortality that varies between 6% and 63% also depending on type of analysis conducted. #PHSymposium17

Limitations Short maximum screening period of 7 years analysed. Small number of deaths and variations in yearly death rates. Quality issues in causes of deaths of death certificates and changes over time. The ecological nature of the study did not permit analysis of individual factors which could contribute to reduced mortality. Includes deaths in women with breast cancer diagnosed before the introduction of screening. However results of randomised trials have often shown divergence of mortality-rate curves of the invited and control groups within the first 1–3 years of screening.2However, in randomized, controlled trials, there was a reduction in mortality after 4 years, with an increasing effect up to 10 years #PHSymposium17

Discussion and recommendations This can be considered as a first step in the evaluation of impact of screening, however further analysis at a later stage and more specific analysis should be undertaken to be able to quantify screening benefits. Our results suggest that the investment in the programme is reaping benefits and encourages further development of the service. #PHSymposium17

Acknowledgments Malta National Cancer Registry Malta National Health Screening Services Thank you #PHSymposium17