New Genetic Test Could Help Millions Avoid Chemotherapy

For millions of women diagnosed with breast cancer, the path to recovery often includes chemotherapy. While this treatment is effective at preventing the disease from returning, it also comes with difficult side effects. Patients often suffer from hair loss, extreme tiredness, and physical pain. Some may even face long-term health issues, such as early menopause or problems with memory and thinking. For decades, doctors have had few ways to know exactly which patients truly need this intense treatment and which could safely avoid it.

However, a new international study, known as the Optima trial, suggests that a groundbreaking genomic test could change everything. The test, called Prosigna, looks at the activity of 50 specific genes within a patient’s tumour. By analyzing these genes, the test determines the “molecular subtype” of the cancer—essentially its biological makeup—and provides a score that tells doctors how likely the cancer is to return within the next ten years. According to The Guardian Health, this information helps medical teams decide if chemotherapy is necessary or if a patient can be treated with hormone therapy alone.

The trial was large and diverse, involving 4,429 patients aged 40 or older from countries including the UK, Norway, Sweden, Australia, New Zealand, and Thailand. All participants had a common form of breast cancer that responds to hormones, which makes up about 80% of all breast cancer cases globally. The researchers split the participants into two groups. One group received the standard treatment of chemotherapy followed by hormone therapy. The other group had their tumours analyzed by the genomic test. If the test showed a low risk, those patients skipped chemotherapy and used only hormone therapy.

The results, which are being presented at the American Society of Clinical Oncology’s annual meeting in Chicago, are very positive. The Guardian Health reports that the five-year survival rate for the group that skipped chemotherapy was 93.7%. This was statistically very similar to the 94.9% survival rate seen in the group that received chemotherapy. These findings suggest that many women can safely avoid the physical and emotional burden of chemotherapy without increasing the risk of their cancer coming back.

For many patients, this news brings a sense of great relief. Karen Bonham, a 64-year-old retired speech and language therapist from Wales, was one of the participants in the trial. She was diagnosed with breast cancer in 2017 and was only days away from starting chemotherapy when she received a phone call from her hospital. The results of her genomic test showed that she did not need the treatment. Describing her reaction to The Guardian Health, she said the news felt “like Christmas.” Today, nine years after her diagnosis, she remains healthy, active, and free of cancer. She credits the trial for allowing her to live a full life without the long-term effects of chemotherapy.

Prof Rob Stein, the chief investigator of the trial and a professor of breast oncology at University College London, explained that this study addresses a long-standing challenge in cancer care. He noted that the findings allow doctors to use tumour biology to guide their decisions, rather than relying only on traditional clinical methods. By using this evidence-based approach, health systems can use their resources more effectively, and patients can avoid unnecessary, toxic treatments.

It is important to note that this test is not for everyone. The Guardian Health clarifies that for some patients, chemotherapy remains a necessary and important part of their treatment plan. The test is a tool to help doctors make better, more personalized decisions based on the specific biology of a patient's cancer. As the medical community looks toward the future, this study marks a significant step in the era of personalized medicine. By identifying who truly benefits from chemotherapy, doctors can ensure that patients receive the right care at the right time, improving both their survival rates and their quality of life.