Around 70% of women with the most common type of breast cancer could be spared chemotherapy, a new study has found.
Following trials of a genetic test that analyses the danger of a tumour, it was discovered that thousands of women could avoid chemo using under a new “precision medicine” approach.
The genetic test, Oncotype Dx, gives women a score between 0 and 100. Currently, women who get a low score are advised they do not need chemo. Those with a high score are told they definitely do.
However, most women get a mid-range score and generally have chemotherapy.
But the new study has revealed that these women have the same survival rates with or without chemo. This was particularly the case for women aged over 50.
The nine-year-survival-rate was 93.9% without chemotherapy and 93.8% with chemotherapy.
Cancer doctors said the findings would change practice in UK clinics on Monday, while charities said the news, affecting 3,000 UK women a year, was "wonderful".
Speaking about the findings of the study, which was published in the New England Journal of Medicine, Rachel Rawson, from the charity Breast Cancer Care, said: "Every day, women with certain types of breast cancer face the terrible dilemma of whether or not to have the treatment, without hard facts about the benefit for them.
"This life-changing breakthrough is absolutely wonderful news as it could liberate thousands of women from the agony of chemotherapy."