Women in England and Wales with a strong family history of breast cancer could be offered a drug on the NHS to try to prevent the disease.
The National Institute of Health and Clinical Excellence (NICE) has launched a consultation on whether Tamoxifen could be given for up to five years.
If approved later this year, the draft guidelines would be the first of their kind in the UK.
NICE says not enough is being done to help healthy but high-risk women, who include women with a sister and a mother or aunt diagnosed with breast cancer before the age of 50.
Taking Tamoxifen for five years could cut their own risk of the disease.
Breast cancer is the most common cancer in the UK, with about 50,000 women and 400 men diagnosed with the condition each year.