Exciting findings show that tamoxifen has increased survival rates when taken for 10 years rather than the current five years.
Dr Julia Wilson, Director of Research at Breakthrough Breast Cancer, said: "These findings are extremely exciting for women who are diagnosed with the most common type of breast cancer.
"The study proved that 10 years of taking tamoxifen has a much higher survival rate than the current five years, which is vital in helping us to stop breast cancer coming back and, more importantly, to help us stop women dying from breast cancer.
"Tamoxifen is a well-established and cheap treatment, which means the guidelines for usage should be easy to amend. We do however encourage all women taking this treatment to speak to their doctor about their individual circumstances as there can be side effects involved."
More information about targeted treatments like tamoxifen can be found in the research section of our website.