Breast cancer can return 20 years after a woman is first diagnosed, a study has revealed.
Oxford University researchers found the disease can ‘lie dormant’ for years, reappearing long after patients are given the all-clear.
Scientists said in future women might be told to continue taking hormonal drugs for longer than the current five years, in a bid to stop tumours returning.
Scientists analysed data from 88 clinical trials involving 62,923 women, all of whom had the most common form of breast cancer fuelled by the hormone oestrogen.
Every patient received pill treatments such as tamoxifen or aromatase inhibitors which block the effects of oestrogen or shut off the hormone’s supply.
After five years of therapy, their cancers had gone and they stopped taking the drugs.