New DNA Test May Spare Millions from Chemotherapy
Millions of individuals diagnosed with breast cancer could potentially avoid chemotherapy safely, following the development of a DNA test that differentiates patients likely to benefit from chemotherapy from those who are not. This conclusion is based on the results of a recent international trial.
The study revealed that over two-thirds of participants could be treated solely with hormone therapy, thus avoiding the adverse side effects associated with chemotherapy.
Chemotherapy is known to cause a range of side effects including fatigue, nausea, hair loss, a compromised immune system, and fertility complications.
Details of the Study
Led by University College London (UCL), the trial involved more than 4,000 newly diagnosed breast cancer patients aged over 40 from the UK, Norway, Sweden, Australia, New Zealand, and Thailand.
According to UCL, researchers estimate that over 5,000 NHS patients annually could avoid chemotherapy as a result of the trial’s findings.
The scientists employed a gene test named Prosigna, which measures the activity of 50 genes implicated in breast cancer progression. This test calculates a patient’s risk of cancer recurrence.
Participants who received a low-risk score—comprising two-thirds of the group—were not administered chemotherapy. Their five-year survival rate was 93.7%, compared to 94.9% among those who underwent chemotherapy.
Current Treatment Practices and Concerns
Surgery to remove tumors is typically the primary treatment for breast cancer. Chemotherapy is often recommended post-surgery to reduce the likelihood of cancer returning.
Chemotherapy is also commonly offered to patients with early-stage breast cancer that has spread to nearby lymph nodes.
However, clinicians have expressed concern that chemotherapy may provide limited benefit to patients with the most common type of breast cancer, as noted by UCL.
Patient Impact and Personal Stories
UCL reiterated that more than 5,000 NHS patients annually could avoid chemotherapy due to the trial’s outcomes.
Karen Bonham, a 64-year-old participant from Cardiff, described the results as an "immense relief" and likened the news to "Christmas." She avoided chemotherapy through the Prosigna test and instead received eight years of radiotherapy and hormone therapy.
"Cancer diagnosis and treatment can be shocking," she said. "It certainly propels you into a world of uncertainty. Life priorities realign - you simply want to survive."
Presentation and Expert Commentary
The study’s findings are scheduled to be presented at the American Society of Clinical Oncology's annual meeting, the world’s largest cancer conference, held in Chicago, United States, on Saturday.
Professor Rob Stein, the trial’s chief investigator and professor of breast oncology at the UCL Cancer Institute, commented on the significance of the results:
"These results mark an important and significant step toward more personalised treatment.
The trial has successfully used tumour biology to guide decisions rather than relying solely on traditional clinical features.
For patients, this means many may be spared the physical and emotional burden of chemotherapy and its potential long-term side effects.
For health systems, it represents a more efficient and evidence-based use of resources."
Limitations and Future Research
It remains unclear whether these findings are applicable to patients under the age of 40. According to UCL, results regarding this younger demographic are expected in several years.
