(CSPOT33) Incidence, Prevalence, and Survival of Breast Cancer in the United Kingdom from 2000-2021: A Population-Based Cohort Study

Background: Breast cancer is the most frequently diagnosed cancer in females globally. However, we know relatively little about trends in males. This study describes UK secular trends in breast cancer from 2000-2021 for both sexes.

Objectives: To describe breast cancer incidence, prevalence and survival (at 1, 5 and 10 years after diagnosis) from 2000-2021 in the UK for both females and males using electronic health record data from primary care.

Methods:

Design: Population-based cohort study.
Setting: UK primary care Clinical Practice Research Datalink (CPRD) GOLD database from 2000 to 2021. The source population included 5848436 eligible females and 5539681 males aged 18+ years, with ≥one year of prior data availability in the study period.
Exposures or interventions: None.
Main outcome measures: Diagnostic codes of breast cancer events.
Statistical analysis: We estimated breast cancer incidence rates (IR), period prevalence (PP) and survival at 1, 5 and 10 years after diagnosis using the Kaplan-Meier method. Incidence and prevalence analyses were stratified by age (y: years), and survival estimates were stratified by calendar time.

Results: IR of breast cancer from 2000-2021 was 194.4 per 100000 person-years for females and 1.16 for males. PP in 2021 was 2.1% for females and 0.009% for males. Both sexes have seen around a 2.5-fold increase in PP across time. Incidence increased with age, peaking in females aged 60-69y and males 90+. There was a drop in incidence for females aged 70-79y. From 2003-2019, incidence increased >2-fold in younger females (aged 18-29: IR 2.12 [95%CI 0.85 - 4.37] in 2003 vs 4.58 [2.37 - 8.00] in 2018); decreased in females aged 50-69y; and further declined from 2015 onwards in females aged 70-89y. Survival for females after 1, 5, and 10 years after diagnosis was 95.1% [94.99 - 95.28], 80.2% [79.88 - 80.49], and 68.4% [68.02 - 68.86], and for males 92.9% [90.67 - 95.26], 69.0% [64.50 - 73.87], and 51.3% [45.55 - 57.87]. Survival at 1 year increased by 2.08% points, and survival at 5 years increased by 5.39% from 2000-2004 to 2015-2019 for females, particularly those aged 50-70y. For males, there were no clear time-trends for short-term and long-term survival.

Conclusions: Incidence of breast cancer in females largely reflect the success of screening programmes: rates rise and fall in synchronicity with ages of screening eligibility. Overall survival from breast cancer for females has improved from 2000-2021, reflecting success of screening programmes, early diagnosis, and improvements in treatments. Male breast cancer patients have worse survival outcomes compared to females, highlighting the need to develop male-specific diagnosis and treatment strategies to improve long-term survival in line with females.