P99 Changing epidemiology and age-specific incidence of breast cancer in England, 1985–2018

Background - Although the incidence of breast cancer has been steadily increasing in most countries over the past four decades, there is an indication of stabilisation in some of the Western countries (i.e. France, Italy, Norway, USA) in recent years. We conducted a retrospective population-based cohort study to examine whether there have been changes in the incidence of breast cancer in England during the past four decades. Methods - Individual level data for women diagnosed with breast cancer in England during 1985–2018 were obtained from the Office for National Statistics/Public Health England. Average annual incidence rates were calculated by two age categories (0–49, 50+ years) during the six five-year time periods (1985–89 to 2010–14) and the recent four-year period (2015–18). The percentage change in incidence was calculated as change in the average incidence rate from the first (1985–89) to the last time period (2015–18). Results - During the 34-year study period, a total of 1,218,109 women with breast cancer were registered in England. In women aged 0–49 years, the average annual incidence rates increased by about 50% (from 32.6/100,000 in 1985–89 to 48.8/100,000 in 2015–18); and in women aged 50+ years, the rates increased by 47% (from 241.3/100,000 in 1985–89 to 355.5/100,000 in 2015–18). There was some indication that the rates, particularly in younger women, may be stabilising (or levelling off). With regards to the levels of deprivation, least deprived women were more likely to be diagnosed with breast cancer, compared to those who were most deprived (23.0% versus 15.2%). Conclusion - It appears that, like some other western countries, incidence rates of breast cancer in England, particularly among young women, may be stabilising (or levelling off). The relatively increased risk of breast cancer among least deprived women is consistent with that reported from other Western countries.