Genomic Testing Could Spare Millions of Breast Cancer Patients from Chemotherapy
A new international clinical trial is raising hopes that millions of women diagnosed with breast cancer may be able to avoid chemotherapy without reducing their chances of survival.
Presented at a major cancer conference in Chicago, the study found that genomic testing can help identify patients who are unlikely to benefit from chemotherapy, allowing them to receive less intensive treatment while achieving similar outcomes.
Breast cancer is the most diagnosed cancer among women worldwide, with the World Health Organization estimating about 2.3 million new cases and 670,000 deaths every year. In Kenya, an estimated 6,000 to 7,000 women are diagnosed annually, while between 2,500 and 3,000 die from the disease, often because it is detected at an advanced stage.
For decades, chemotherapy has been a standard part of breast cancer treatment, particularly after surgery to remove a tumour. While the treatment can be life-saving, it is also associated with severe side effects, including fatigue, nausea, hair loss, infections, infertility, early menopause and long-term cognitive problems.
Doctors have traditionally relied on factors such as tumour size, grade, lymph node involvement and patient age to determine whether chemotherapy is necessary. However, these indicators do not always accurately predict which patients will benefit from the treatment.
The new study suggests that analysing the genetic activity of a tumour may provide a more precise way of making treatment decisions.
Researchers enrolled women aged 40 years and older who had hormone receptor-positive breast cancer, the most common form of the disease, accounting for nearly 80 per cent of all breast cancer cases.
Participants were randomly assigned to one of two treatment groups. The first received standard care, which included chemotherapy followed by hormone therapy. The second underwent genomic testing, which examined the activity of 50 genes within the tumour and generated a score estimating the risk of the cancer returning over the next 10 years.
Patients identified as high-risk received chemotherapy alongside hormone therapy, while those classified as low-risk were treated with hormone therapy alone. Other treatments, including radiotherapy, were provided equally to both groups.
After five years of follow-up, researchers found virtually no difference between the two groups.
Approximately 95 per cent of patients who received chemotherapy and hormone therapy remained alive and free of cancer recurrence, compared with 94 per cent of those who received hormone therapy alone based on genomic test results.
The findings suggest that chemotherapy may provide little additional benefit for many patients classified as low-risk through genomic testing.
Researchers say the results represent an important step towards personalised cancer treatment, where therapies are tailored to the biological characteristics of each patient’s tumour rather than relying solely on traditional clinical measures.
The study also highlights the potential to improve quality of life for patients by reducing unnecessary exposure to the physical and emotional burden of chemotherapy.
One participant in the trial described learning that chemotherapy could safely be avoided as a moment of immense relief. Years after treatment, the patient remains cancer-free and continues to lead a normal life.
Cancer specialists believe the findings could help resolve one of oncology’s biggest challenges: determining which patients genuinely need chemotherapy and which can be spared the treatment without compromising outcomes.
Beyond the benefits to patients, reducing unnecessary chemotherapy could also lower healthcare costs and ease pressure on overstretched cancer services.
However, experts caution that a longer follow-up is needed to confirm the results over a longer period. Questions also remain about how widely genomic testing can be implemented in low- and middle-income countries, where access to advanced diagnostic technologies remains limited.
Despite these challenges, the study reflects a broader shift in cancer care towards precision medicine. By understanding the genetic behaviour of tumours, clinicians are increasingly able to match patients with treatments that offer the greatest benefit while avoiding therapies that may be unnecessary.
