A genetic test can help predict whether patients with the most common type of breast cancer will benefit from chemotherapy, a new study suggests.
The EndoPredict tool, which analyses the makeup of tumours to detect whether a woman is at a high risk of the disease spreading, could save some from undergoing unnecessary treatment, the researchers said.
It is hoped the test could help doctors make decisions about the most effective treatment for patients with oestrogen receptor positive, HER2 negative (ER+/HER2-) disease.
Professor Daniel Rea, a breast cancer expert from Cancer Research UK, said it could be a “valuable addition” to others which are currently available.
The researchers, including a team from Queen Mary University of London, analysed data from three trials involving 3,746 women.
Patients with a high EndoPredict test score – indicating a high risk of the disease spreading – who underwent chemotherapy as well as standard hormone treatment had up to a 33% lower absolute risk of their breast cancer returning within 10 years, compared with those who just had hormone treatment, the study found.
The researchers said the findings, published in journal Breast Cancer Research and Treatment, indicate that a high score can predict chemotherapy benefit among women with this form of breast cancer.
Dr Ivana Sestak, lead author from Queen Mary University of London, said: “It is clinically important to determine which women with hormone receptor positive, HER2-negative breast cancer need chemotherapy in addition to standard five years of hormonal treatment.
“We have shown that EndoPredict has the ability to predict chemotherapy benefit, which will ultimately help clinicians in their decision-making process about adjuvant treatment.”
Prof Rea, from Cancer Research UK, said: “This important study is one of the few to provide not just information on the risk of a patient’s breast cancer coming back, but also whether their cancer is likely to be sensitive to chemotherapy.
“The EndoPredict test has the potential to help some women diagnosed with early hormone receptor positive, HER-2 negative breast cancer, avoid needless chemotherapy, and may reassure those where it’s needed.
“This research highlights the progress being made in genetic testing and could be a valuable addition to the current tests available to doctors, helping them advise patients on the best treatment.
“Trials in the UK are ongoing to provide more evidence to help us make the best use of these tests.”
Baroness Delyth Morgan, chief executive at Breast Cancer Care and Breast Cancer Now, said: “These promising findings offer the first indication that EndoPredict could also identify which patients will respond to chemotherapy, as well as whether they are at a higher risk of recurrence.
“While this test is already recommended for use on the NHS, it’s exciting that it may have even greater potential in guiding decisions about whether chemotherapy is necessary.
“Chemotherapy remains a cornerstone of treatment, but with such difficult side effects including hair loss, fatigue and possible infertility, it’s essential we avoid giving it to patients who will see little benefit.
“Genomic tests like this are therefore invaluable in giving patients and their doctors greater reassurance and peace of mind in decisions about chemotherapy and helping ensuring patients receive the most appropriate treatment for them.”