A leading research team, primarily funded by Breast Cancer Now, has discovered an improved way of predicting risk of breast cancer recurrence following standard five-year hormone treatment using information from a test already being used within the NHS.
The Oncotype DX test, which analyses 21 different genes, is widely used to predict the likelihood of a breast cancer returning in another part of the body – or spreading – in patients treated with hormone therapy. These test results are then used to identify those women that would benefit from chemotherapy to reduce this risk, and spare others from needless, toxic treatment.
Hormone therapy for five years is the standard of care for women with oestrogen receptor (ER) positive breast cancer – which accounts for around 80% of all breast cancer cases – and, while some women benefit from hormone therapy beyond five years, we don’t yet know how to select them.
This latest research, led by teams at The Institute of Cancer Research, London and The Royal Marsden, has shown that levels of ER expression – just one of the genetic markers that the Oncotype DX test picks up – had a substantial effect on risk of the disease recurring and may be useful in determining who may or may not benefit from extended therapy.
Interestingly, the team found that patients with high ER levels showed a relatively low recurrence rate in the first five years, but this was followed by an approximate doubling of risk in the next five years. This shows that recurrence in these patients might be restricted simply by extending their treatment beyond five years.
Conversely, patients with relatively low ER expression showed a constant risk of recurrence across the 10 year period.
The research was published in Clinical Cancer Research and funded by the Mary-Jean Mitchell Green Foundation, Breast Cancer Now, AstraZeneca, the NIHR Biomedical Research Centre at The Royal Marsden and The Institute of Cancer Research and Cancer Research UK.
Professor Mitch Dowsett, Professor of Biochemical Endocrinology at the ICR and Head of the Academic Department of Biochemistry at The Royal Marsden, said: “Our study, of more than 1,300 women with oestrogen receptor positive breast cancer, indicates that women with high levels of the oestrogen receptor might benefit from extended treatment with hormone therapy – which usually stops after five years. The Oncotype DX test, which we used in our study and has recently become available on the NHS, could with modification be used to detect which women are in this group.
“While we know that some women benefit from extended treatment, it is also clear that many suffer side-effects from treatment. We urgently need to bring new ways of identifying which women would benefit from extended treatment into routine use as quickly as possible.”
Dr Matthew Lam, Senior Research Communications Officer at Breast Cancer Now, said: “Oncotype DX is already being used by doctors to help make the best treatment decision for each patient, so there’s no reason why this new use for the test couldn’t quickly and easily be integrated into clinical practice in the future.
“Research like this is constantly improving the accuracy of each patient’s diagnosis so it’s important that the standard of care is adapted accordingly. Personalised medicine is the direction we need to be moving in if we are going to give breast cancer patients the best chance of survival, and ultimately outwit this disease once and for all in the future.”
Oncotype DX was approved by the National Institute for Health and Care Excellence (NICE) for use on the NHS in England and Wales in September 2013 as a cost effective tool to determine a patient’s risk of breast cancer recurrence.
Breast Cancer Now is the UK’s largest breast cancer charity, created by the merger of Breast Cancer Campaign and Breakthrough Breast Cancer.