Case study: Early breast cancer patients at high risk of recurrence
Overview
Breast cancer is the most common cancer in the UK, accounting for around 15% of all new cancer diagnoses. The majority of patients, approximately 9-%, are diagnosed at an early stage when curative treatment is possible. The most common subtype is hormone receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer, which represents approximately 70% of all cases.
Despite generally favourable outcomes, early breast cancer, a subset of patients face a significantly higher risk of recurrence. For people with node-positive HR+, HER2- early breast cancer, treatment decisions are complex and must balance potential benefits with long-term risks. Standard care typically includes combinations of surgery, radiotherapy, chemotherapy and adjuvant endocrine therapy (AET), tailored to an individual’s risk of relapse and expected response to treatment.
While advances such as aromatase inhibitors and extended durations of endocrine therapy have improved outcomes over the past two decades, many patients with high-risk disease continue to experience recurrence over long timeframes. Understanding how these patients are treated in real-world clinical settings, and how they fare over time, is critical to improving care and informing future treatment decisions.
This study set out to better understand the characteristics, treatment patterns and long-term outcomes of patients with high-risk early breast cancer in Scotland using routinely collected healthcare data.
Who is involved?
The study was led by the University of Edinburgh in collaboration with Edinburgh Cancer Informatics. It was funded by Eli Lilly and focused on patients treated through the Edinburgh Cancer Centre, a specialised referral facility serving South-East Scotland.
Data access and analysis were supported through DataLoch, which provided a secure environment for the use of NHS data and supported governance processes including disclosure checks before results were published.
What data is being used?
The research involved a retrospective analysis of routinely collected healthcare data from approximately 4,600 patients diagnosed with early breast cancer between 2005 and 2020.
The study focused on patients with node-positive HR+, HER2- disease who met high-risk criteria aligned with the monarchE Cohort 1 definition.
Demographic, clinical and treatment information was drawn from several linked datasets, including:
- The cancer registry
- The South-East Scotland Cancer Database (SESCD)
- The SCAN audit
These datasets enabled researchers to examine treatment patterns, long-term outcomes including invasive disease-free survival (IDFS) and overall survival extending up to ten years, and healthcare resource use in a real-world Scottish population.
What have they found?
Analysis of real-world data from South-East Scotland showed that patients with node-positive HR+, HER2- early breast cancer who met high-risk criterial experienced unfavourable long-term outcomes, consistent with findings from clinical trial populations.
The study identified a clear unmet clinical need for more effective therapeutic options for this patient group. By documenting treatment patterns and outcomes over extended follow-up periods, the research provides important evidence to support clinical decision-making and health technology assessments in Scotland.
The findings also strengthen the evidence based used by organisations such as the Scottish Medicines Consortium when evaluating new treatments. This supports more informed decisions about patient access to emerging therapies.
Challenges and limitations
As a retrospective study, the analysis was limited by the information available with existing datasets. Some high-risk characteristics were not captured due to study methodology, which may have influenced outcome estimates.
The patient population represents a historical cohort spanning 2005 to 2021, meaning results must be interpreted carefully when compared with contemporary clinical practice. To reduce potential bias, patients who received abemaciclib through the monarchE trial were excluded, and participation in other major adjuvant CDK4/6 inhibitor trials was limited in the study region.
Differences in baseline characteristics were also observed. Patients in the real-world dataset had a higher median age and a greater proportion of post-menopausal women compared to clinical trial populations. These differences likely reflect real-world treatment patterns rather than clinical trial selection criteria.
Why does this matter?
By providing a detailed picture of how high-risk early breast cancer is treated in routine clinical practice, this study helps bridge the gap between clinical trial evidence and real-world outcomes.
The findings support the need for continued innovation in treatment approaches and provide critical evidence to inform policy decisions, drug evaluations, and patient care. Real-world data analysis of this kind strengthens the evidence based used by clinicians, regulators and healthcare decision-makers when evaluating new cancer therapies.
More information
Image credit: Breast cancer cells, National Cancer Institute. Source: Unsplash.