Vickram S. Tittrea, PhD¹; Deborah Wyatt, BA¹; Tamara Nicholls, BA¹; Elisa Nevalainen, PhD²; Caroline O'Leary, MSc¹

Author Affiliations:

¹ IQVIA, The Point, 37 N Wharf Rd, London W2 1AF, United Kingdom

² IQVIA, Metsänneidonkuja 6, 02130 Espoo, Finland

One in seven

That is the lifetime odds a woman in the UK will hear the words: you have breast cancer.

In 2026, the scale of the challenge reached a stark new milestone. For the first time, more than 400,000 people are diagnosed with cancer in the UK every year, and breast cancer remains the most common of them all, with around 59,400 new cases annually, roughly 160 every single day [1,2].

But behind each of those numbers is a moment that never makes it into a dataset: the pause in a consulting room, the word diagnosis landing, an ordinary day splitting into a before and an after. This blog is about what happens next. How far treatment has come, why so much of a patient’s real experience still goes unrecorded, and how the right evidence can make each of those 160 daily diagnoses a little less frightening and a great deal more survivable.

Progress that has not reached everyone equally

Breast cancer remains the most common cancer among women worldwide, with approximately 2.3 million new cases and around 670,000 deaths globally in 2022 [3]. But the burden is uneven. Women from more deprived communities face barriers to timely screening and diagnosis, while some ethnic minority groups experience differences in disease presentation and access to services [4]. In England, five-year survival is 89.6% among women in the least deprived areas, against 82.6% in the most deprived [4,5]. Age tells a similar story: around 76% of women diagnosed between 15 and 44 survive 10 years or more, against 54% of those diagnosed between 75 and 99 [5].

Randomised controlled trials are essential in demonstrating efficacy and safety, but they answer specific questions under controlled conditions, in selected populations that may not reflect real-world patients. They can show whether a treatment works; they are far less able to show how outcomes differ across ethnic groups, whether access is equitable, or what drives adherence in routine care.

That is the gap real-world evidence (RWE) fills. By analysing electronic health records, cancer registries, screening programmes and patient-reported outcomes, RWE reveals how care is actually delivered and experienced, and can quantify the impact of health inequalities [4]. It tells us not only whether a treatment works, but who it works for, a question made more urgent by how fast the science has moved.

From one disease to a family of diseases

Breast cancer was once treated largely as a single condition. It is now understood as a family of diseases, each driven by different biology, and that biology increasingly decides which treatment a patient is offered. Precision oncology means selecting treatment from a validated feature of the tumour or of a person’s inherited genes, rather than from the diagnosis alone, which depends entirely on a test being done and on the result arriving in time to change a decision.

Human Epidermal Growth Factor Receptor 2 (HER2) reshaped practice first, and for years the result functioned as a simple yes or no [6]. However, the DESTINY-Breast04 clinical trial changed that, studying advanced tumours with only low levels of HER2, too little to count as positive under the old rule [7]. Against chemotherapy of the physician’s choice, trastuzumab deruxtecan delayed progression and extended survival: in the hormone receptor-positive group, a median of 10.1 versus 5.4 months, and 23.9 versus 17.5 months [7,8]. HER2-low is not a new disease, but a treatment-relevant category defined by testing. The biology did not change; how closely we looked at it did.

Inherited risk has become a treatment decision too. Individuals carrying a Breast Cancer gene 1 (BRCA1) or Breast Cancer gene 2 (BRCA2) fault have cells less able to repair their own DNA, and poly(ADP-ribose) polymerase (PARP) inhibitors exploit that weakness [9]. In the OlympiA clinical trial, a year of olaparib after surgery in high-risk, HER2-negative early breast cancer left 85.9% free of invasive disease at three years, against 77.1% on placebo [9]. And in early triple-negative disease, the KEYNOTE-522 clinical trial added pembrolizumab to chemotherapy around surgery: far more patients had no detectable cancer left at surgery, 64.8% versus 51.2% on placebo-chemotherapy [10], followed by improvements in event-free and overall survival [11].

One caveat is worth stating plainly. “Targeted” does not mean “gentle”. The fairer description is treatment better matched to the tumour, not automatically easier to live with [7,9,10]. And the science alone settles nothing: if treatment turns on molecular detail, then who is tested, and when, determines whether any of this reaches the woman in the consulting room. But what reaches her is only part of the story.

The patient voice is evidence

Two of our colleagues have lived this from the other side of the consulting room. Their experiences, eleven years apart, make the same case from different angles.

Why this counts as evidence

Much has changed since Tamara's diagnosis, and Deborah's experience a decade later reflects it. Patients now have a legal right to access their own records at no cost, and shared decision-making is embedded in NICE guidance rather than left to individual goodwill [12,13]. The same principle applies to evidence generation. Regulators, researchers and health technology assessment bodies increasingly recognise the value of patient-reported outcomes, which capture directly from patients what clinicians cannot observe and records do not hold: symptoms, quality of life and treatment burden [14,15].

Clinical data tells us what has happened. When treatment was delivered, whether a tumour responded, how long someone survived. Only patients can tell us whether the outcomes achieved were meaningful. The patient voice is not supplementary to real-world evidence; it is evidence in its own right.

The evidence base: the English Cancer Registry

Patient voice tells us what matters; population data tells us how often, and for whom, it is happening. For breast cancer in England, the English Cancer Registry (ECR) is where that second half of the picture comes together. It provides linked secondary-care data on approximately 99% of cancer patients in England, more than 140 million records [16,17]. That near-total coverage matters, because it reflects the real variation in age, ethnicity and geography that tightly controlled trials are never built to capture. Linked to this is molecular biomarker testing data covering more than 550 solid-tumour biomarkers [18].

The strength lies in how the data connects. Linked NHS datasets trace the patient journey: the Cancer Outcomes and Services Dataset (COSD) records diagnosis and tumour characteristics; the Systemic Anti-Cancer Therapy (SACT) dataset and the Radiotherapy Dataset (RTDS) capture systemic therapy and radiotherapy; Hospital Episode Statistics (HES) document admissions and surgery; the Office for National Statistics (ONS) supplies mortality and survival data [18,19]. Read together, they follow the same patient over time. These cover hospital care, so some treatments given in primary care, such as certain hormone therapies, are not captured. This is no theoretical asset: IQVIA has conducted more than 130 studies using these data.

That linkage lets us describe how treatment genuinely unfolds in routine NHS care: treatment patterns, line-of-therapy sequencing, duration, switching and discontinuation, set against guidelines. ONS supports real-world overall survival; HES captures hospital resource use along the pathway; together they enable comparative effectiveness research in a broad, representative population rather than a trial-eligible subset [20]. Biomarker testing data go deeper into testing patterns as they happen, showing which patients are tested, when, and how their molecular status maps onto treatment [18]. Put simply, the ECR does not just confirm that patients were treated. It shows how they were treated in routine practice.

Beyond England

Breast cancer does not respect borders, and neither should the evidence we build about it. The simplest difference between systems is also the most consequential: who is invited for screening, and how often. England invites women for a first mammogram between 50 and 53, then every three years until 71 [21]. Finland, Denmark and Norway invite women aged 50 to 69 every two years [22,23,24]; Sweden across a wider band, 40 to 74 [25]. These are not administrative footnotes. They shape who is found, and when.

The Nordic countries are unusual in the maturity of their registries, and NORDCAN brings them together with comparable statistics for 41 major cancers [26]. But placing systems side by side is possible, never automatic: what a registry records, and how, can differ even where coverage is strong, and work across the Nordics has proposed harmonisation rather than assumed it [27]. Credible multi-country analysis therefore begins with agreeing common definitions, not with pooling data. Done properly, it increases the cases available for rare biomarker subgroups. The value is not scale for its own sake; it is the ability to ask whether the advances described earlier are reaching comparable patients in comparable ways.

Where this leaves us

Early detection, tailored treatment and robust real-world evidence together add up to better outcomes. The science is advancing quickly, but those advances only translate into survival gains when we can see, at population scale, whether they reach the right patients. That is where IQVIA is placed to partner, from shaping the study question through to delivering the linked, population-level evidence that regulators, payers and clinicians can act on [20].

Yet the purpose of all this data is never the data itself. Think back to the woman hearing the word diagnosis for the first time. Every record, every linkage and every analysis exists to make her pathway clearer, her treatment more precise, and her outcome better than it might otherwise have been. Getting the evidence right is how we honour that moment.

If you would like to explore how ECR-powered real-world evidence could support your organisation, we would be delighted to connect. Please contact us here.

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