Millions of breast malignancy patients could safely forego chemotherapy after scientists created a DNA test that determines who will gain from the treatment and who will not, according to trial results revealed at a major international cancer conference. The landmark research, led by University College London and involving more than 4,000 newly diagnosed patients across the UK, Norway, Sweden, Australia, New Zealand and Thailand, found that more than two out of three of participants could be protected the debilitating side effects of chemotherapy and treated with hormone therapy alone. The gene test, called Prosigna, assesses the activity of 50 genes involved in breast cancer growth to determine a patient’s likelihood of disease recurrence. The findings, which will be presented at the American Society of Clinical Oncology’s yearly conference in Chicago on Saturday, could spare over 5,000 NHS patients each year from unnecessary chemotherapy.
A Significant breakthrough in Personalised Cancer Treatment
The trial results represent a meaningful move toward personalised medicine in cancer care, enabling clinicians to tailor treatment decisions informed by individual genetic profiles rather than applying a one-size-fits-all approach. By identifying patients who are unlikely to benefit from chemotherapy, the Prosigna test enables doctors to protect them against unwarranted administration to toxic drugs whilst maintaining excellent survival outcomes. The five-year survival rate among patients who avoided chemotherapy was 93.7%, compared with 94.9% for those who received it, demonstrating that hormonal treatment by itself can be equally effective for numerous individuals. This distinction is particularly important for early-stage breast cancer, the most prevalent form, where clinicians have long suspected chemotherapy provides limited extra advantage.
Professor David Miles, a prominent cancer specialist, hailed the findings as “practice-changing,” emphasising that doctors can now “confidently define a large population of women who simply won’t benefit” from chemotherapy. The implications extend beyond individual patient outcomes to broader healthcare efficiency and wellbeing. By reducing unnecessary chemotherapy exposure, the NHS could channel resources towards patients who genuinely need aggressive treatment whilst simultaneously improving patient experiences. The test offers particular value given the well-documented side effects of chemotherapy, which include tiredness, sickness, baldness, compromised immune function and risks to fertility that can substantially affect patients’ long-term wellbeing.
- Prosigna test measures activity of 50 genes involved in cancer growth
- Two-thirds of trial participants successfully bypassed chemotherapy therapy
- More than 5,000 NHS patients annually could gain benefit from the test
- Hormone therapy alone demonstrated equivalent effectiveness for low-risk patients
How the Prosigna Assessment Works
Grasping the Scientific Principles Underpinning Gene Testing
The Prosigna test is a significant advance in genomic medicine, leveraging sophisticated genetic assessment to assess the activity of 50 genes specifically involved in breast cancer progression and development. Rather than relying on traditional clinical factors alone, such as tumour size or lymph node involvement, this molecular profiling method delivers a comprehensive molecular portrait of each patient’s cancer. By measuring how these genes are expressed within the cancer tissue, doctors acquire vital information into the clinical behaviour of the disease and its risk of recurrence. This molecular accuracy allows doctors to stratify patients into risk groups with considerable precision, converting clinical decision-making from guesswork into evidence-driven treatment strategies.
The test determines a recurrence score that forecasts the likelihood of cancer recurring over a five-year period, allowing clinicians to differentiate patients who will gain significant benefit from chemotherapy and those for whom hormone therapy alone offers comparable protection. Patients receiving a low score show that their cancer exhibits molecular features linked to strong long-term survival outcomes without aggressive chemotherapy. This genetic categorisation has profound implications, as it demonstrates that many breast cancers, despite being diagnosed as early-stage cancers, lack the aggressive genetic signatures that would warrant the toxicity and burden of chemotherapy treatment. The Prosigna test effectively decodes the molecular language of cancer, converting complex molecular data into actionable clinical guidance.
- Analyses activity levels of 50 genes linked to tumour development
- Produces prognostic score predicting five-year disease recurrence risk
- Determines patients unlikely to respond to chemotherapy treatment
- Allows endocrine therapy only for low-risk category individuals with malignancy
- Offers genetic categorisation in addition to conventional assessment methods
Clinical Trial Findings Reshape Cancer Treatment
The landmark international trial, conducted by University College London and encompassing over 4,000 newly identified breast cancer patients spanning six countries, has yielded results that significantly alter treatment protocols. Researchers discovered that approximately 70 percent of participants—those performing poorly on the Prosigna test—could safely avoid chemotherapy completely and undergo hormone therapy as their sole systemic treatment. This finding demonstrates critical value, as chemotherapy continues to be a typical recommendation after breast cancer surgery, notwithstanding producing considerable side effects including fatigue, nausea, hair loss, immune system suppression, and fertility-related complications. The trial proves that this forceful strategy is unnecessary for a substantial proportion of patients, offering them the opportunity to prevent severe side effects without compromising survival outcomes.
The outcome metrics offer strong support for this fundamental change in patient care. Patients who declined chemotherapy achieved a five-year survival rate of 93.7%, essentially equivalent to the 94.9% rate among those who had chemotherapy as part of their complete treatment approach. This near-equivalence in outcomes suggests that genetic testing can accurately determine patients whose cancer biology does not require standard chemotherapy regimens. The implications extend across the NHS, where specialists calculate that approximately 5,000 patients per year could forego chemotherapy based on these findings. Such a shift would protect thousands from unwanted side effects whilst maintaining excellent long-term survival rates, fundamentally changing the patient experience of breast cancer treatment.
| Patient Group | Five-Year Survival Rate | Treatment Type |
|---|---|---|
| Low-risk score patients (two-thirds of trial) | 93.7% | Hormone therapy alone |
| Chemotherapy recipients | 94.9% | Chemotherapy plus hormone therapy |
| Typical early-stage breast cancer | Variable | Surgery, chemotherapy, hormone therapy |
| Estimated annual NHS beneficiaries | 93.7% | Hormone therapy without chemotherapy |
True Narratives of Relief and Hope
Patient Testimonials
For Karen Bonham, a 64-year-old from Cardiff who took part in the trial, the results felt transformative. Having been given a diagnosis of breast cancer so small it was invisible to the naked eye, she faced the prospect of gruelling chemotherapy treatment. However, the Prosigna test showed she carried a low-risk genetic makeup, sparing her from the ordeal. Instead, she received radiotherapy and hormone therapy over eight years—a far gentler treatment pathway that preserved her standard of living whilst maintaining excellent survival prospects. Bonham characterises the findings as an “immense relief” and feels “like Christmas” at the thought of avoiding chemotherapy’s devastating side effects.
Bonham’s journey encapsulates the psychological burden that a cancer diagnosis inflicts on patients and families. “Cancer diagnosis and treatment can be distressing,” she noted, explaining how the condition “thrusts you into a world of uncertainty.” For many patients, receiving a cancer diagnosis significantly reshapes personal priorities, narrowing them down to a single objective: staying alive. The capacity to attain that survival without undergoing the debilitating effects of chemotherapy—exhaustion, sickness, hair loss, immune suppression, and fertility issues—constitutes a significant change in the patient experience. Bonham’s experience illustrates how genetic analysis can recover not just longevity but life quality throughout treatment.
Expert Perspective on Practice Change
Leading cancer specialist Professor David Miles has characterised these trial findings as “practice-changing,” emphasising their transformative potential for clinical oncology. He explained to the BBC that oncologists can now “confidently predict many patients will get no benefit at all” from chemotherapy, eliminating the need for this aggressive intervention in a substantial patient population. This represents a notable shift from conventional practice, where chemotherapy has continued as standard guidance following breast cancer surgery, largely due to historical uncertainty about which patients truly require it. The Prosigna test finally provides that clarity, allowing clinicians to make individualised treatment decisions based on rigorous genetic evidence.
The movement towards genetically-informed treatment protocols demonstrates a broader progression in oncology towards precision oncology. Rather than delivering chemotherapy universally as a preventative measure, clinicians can now confidently pinpoint the significant population of women who simply won’t benefit from such aggressive treatment. This approach represents not merely a improvement of current practice but a radical reimagining of how breast cancer treatment is understood and administered. By sparing two-thirds of patients from unnecessary chemotherapy whilst preserving survival outcomes, the trial confirms a more thoughtful, individualised approach to oncology care that prioritises both efficacy and patient welfare.
What This Implies for the NHS and Further Afield
The consequences of this trial reach far beyond outcomes for individual patients, with significantly transformative effects for the NHS and health systems worldwide. University College London projects that more than 5,000 NHS patients annually could prevent chemotherapy as a direct consequence of introducing the Prosigna test into standard diagnostic protocols. This demonstrates not merely a clinical progress but a significant reduction in medical burden, as chemotherapy treatment necessitates close medical oversight, supportive care management, and considerable resource commitment. By determining patients who won’t gain benefit from this expensive, labour-intensive intervention, the NHS could reallocate considerable resources towards alternative cancer treatments and services, whilst simultaneously improving patient outcomes through reduced side effects and better quality of life.
The international reach of this research—involving participants from the United Kingdom, Norway, Sweden, Australia, New Zealand, and Thailand—suggests that these results demonstrate significance across diverse healthcare systems and populations. The uniformity of findings across multiple countries and healthcare contexts strengthens confidence in the test’s applicability globally. As cancer care increasingly moves towards personalised treatment approaches, the Prosigna test demonstrates how genomic analysis can democratise access to personalised treatment decisions, ensuring that patients worldwide gain access to research-supported individualisation rather than standardised chemotherapy protocols. This trial therefore positions genetic testing as an vital element of contemporary breast cancer care internationally.
- Over 5,000 NHS patients each year could sidestep chemotherapy through Prosigna testing implementation
- Significant healthcare resources could be redirected from avoidable chemotherapy to other cancer services
- International trial results suggest global applicability across diverse healthcare systems and populations