A DRUG routinely given to women battling breast cancer boosts chances of surviving the disease for at least 10 years, an Oxford study has found.

Last night, a mother-of-three who started taking the drug 15 years ago said it had given her precious extra years.

Trials involving more than 20,000 women with breast cancer showed that an early course of tamoxifen reduced the risk of dying by a third over a 15-year period.

Tamoxifen is usually given for five years following surgery, and only works against breast cancers that are fuelled by the female sex hormone oestrogen, or ER-positive cancer.

Breast cancer is known to return after several years absence but according to the test by Oxford University scientists, tamoxifen can prevent this happening.

Dr Christina Davies, a member of the international research team from the university, said: “This study shows tamoxifen produces really long-term protection.

“For ER-positive disease, tamoxifen reduces 15-year breast cancer mortality by at least a third, whether or not chemotherapy is given.”

About three-quarters of breast cancers are hormone-sensitive. Each year, around 46,000 women in the UK are diagnosed with breast cancer and more than 12,000 die from the disease. About 400 people are diagnosed in Oxfordshire alone.

The trials were carried out by the Early Breast Cancer Trialists Collaborative Group. It studied data from 20 trials around the world.

In all the trials, patients had their long-term progress monitored. Tamoxifen substantially reduced breast cancer death rates well beyond 10 years.

Sylvia Chisnall, from Carterton, was diagnosed with cancer when she was 44.

After undergoing surgery at the Churchill Hospital, she was prescribed a course of tamoxifen.

She said the drug might not work for everyone, but had given her precious extra years to spend with her family.

Mrs Chisnall, now 58, said: “I was told it could have side effects, such as weight gain and nausea, but to be perfectly honest I was fine. You take it because you hope it might prolong your life and allow you to do things you want to do. It has given me a lot more years. And I have done things that I wanted to do, such as own horses again.

“Life is short. If you have been given extra time, make the most of it.”

Dr Caitlin Palframan, policy manager at the charity Breakthrough Breast Cancer, said she was pleased to see such impressive results involving tamoxifen.

She added: “While it’s not suitable for every patient, we are delighted that tamoxifen continues to make such a significant contribution to treating breast cancer.

“We are continuing to strive for breakthroughs in new treatments, so that women have even more options available.”