(SLB-021) Characterization and Incidence of Breast Cancer Amongst Females in the United Kingdom: An Analysis of Real-World Data from THIN® UK Database and Comparability with Findings from the CPRD GOLD Database

Background: Breast cancer is the most common cancer among females in the United Kingdom (UK), with one in seven women expected to be diagnosed with the disease in their lifetime.

Objectives: To determine patient characteristics and incidence of breast cancer amongst females in The Health Improvement Network (THIN®) UK database and to assess the comparability of these findings with data from the Clinical Practice Research Datalink (CPRD) GOLD database.

Methods: This is a population-based cohort study utilizing the THIN® UK primary care database, mapped to the Observational Medical Outcomes Partnership Common Data Model (OMOP CDM). Female patients aged 18 years and older with a diagnosis of primary breast cancer with at least one year of prior clinical history available were included. The study period commenced on 1st January 2011 and patient follow-up continued until database exit, death, or the study end date (1st January 2023). European age standardized annual incidence rates (IR [95%CI] per 100,000 person-years) were calculated and then compared with the previously published annual IR of breast cancer amongst females in the UK primary care CPRD GOLD database mapped to OMOP CDM by Barclay et al, 2024.

Results: THIN® UK included 10,977,326 patients, while CPRD GOLD consisted of 17,267,137 patients. The female breast cancer cohort was larger in CPRD GOLD, with 81,157 cases, compared to 44,444 in THIN® UK. Across both databases, the majority of breast cancer cases were female, comprising 99.3% in THIN® UK and 99.4% in CPRD GOLD. Median ages at diagnosis were similar across the two databases (64 years in THIN® UK vs 63 years in CPRD GOLD). The top three medications prescribed in the year prior to diagnosis showed similar usage rates across databases: systemic antibacterials (THIN® UK: 39.50%, CPRD GOLD: 39.90%), drugs for acid-related disorders (THIN® UK: 32.60%, CPRD GOLD: 28.20%), and opioids (THIN ® UK: 25.20%, CPRD GOLD: 25.60%).

IR [95%CI] per 100,000 in THIN® UK declined from 226.47 [220.59-232.48] in 2011 to 185.40 [176.55- 194.57] in 2022. Similarly, IR in CPRD GOLD decreased from 204.47 [197.84-211.28] in 2003 to 169.67 [162.28-177.30] in 2022. During the 2020 COVID-19 pandemic, a notable drop in IR was observed in both databases: THIN® UK recorded an IR of 81.72 per 100,000 (95% CI: 78.14 to 85.43) and CPRD GOLD an IR of 77.06 per 100,000 (95% CI: 73.78 to 80.45). These declines were followed by a rebound in 2021, with IR rising to 185.20 per 100,000 (95% CI: 177.16-193.51) in THIN® UK and 185.43 per 100,000 (95% CI: 177.95-193.14) in CPRD GOLD.

Conclusions: Real-world data from THIN® UK and CPRD GOLD primary care databases confirm similar breast cancer patient profiles and a declining trend in breast cancer incidence among females in the UK.