Thousands of people in the UK could be spared chemotherapy thanks to a new test which predicts how likely breast cancer is to return.
The test costs $116, and gives cancer sufferers who have undergone surgery reassurance that their cancer is gone for good.
It works by measuring their response to short-term hormone therapy drugs which are used to stop the production of oestrogen growth which can stimulate tumour growth.
By measuring the changes in the growth rate of cancer cells while on the drugs for two weeks, the test can predict how likely the cancer is to return.
The findings, published in The Lancet Oncology journal, were based on a study of 4480 patients in 130 UK hospitals.
It costs less than a twentieth of the tests currently available for people with breast cancer, reports The Daily Mail.
The researchers behind the test say they hope it will become a major part of cancer care in the coming years.
"A new way to help predict if [breast] cancer will return means doctors could monitor these patients more closely," said Professor Arnie Purushotham of Cancer Research UK.
"Catching any sign of cancer as early as possible is crucial for improving survival."