A hormone-blocking drug could save many breast cancer patients from undergoing a mastectomy, a study has shown.
Anastrozole could be more effective than tamoxifen in treating breast cancer.
The drug anastrozole, or Arimidex, reduced or completely shrunk breast tumours in 50% of women involved in a clinical trial.
It was also found to be more effective than the usual drug of choice tamoxifen in reducing the size of breast cancer tumours.
The study was conducted by drug company AstraZeneca, who manufacture Arimidex.
The study findings coincide with the release of a separate survey of 500 women by NOP Research.
This found most women feared losing a breast if diagnosed with breast cancer.
Less extensive surgery
The clinical trial involved 451 post-menopausal women with hormone-sensitive cancer, that had spread beyond the breast.
It compared the effectiveness of anastrozole to tamoxifen 12 weeks prior to surgery.
Findings revealed 43% of those taking anastrozole were able to have less extensive surgery due to a reduction in the size of the tumour, as opposed to 31% in the tamoxifen group.
This meant some women were able to have breast conserving surgery rather lose their entire breast.
Professor Ian Smith, head of the breast unit at the Royal Marsden Hospital, who was involved in the trial said it is a huge morale booster for women when they see the size of their cancer shrink.
"There is no question about it. This should be an option for doctors in treating this type of breast cancer," he told press.
The study confirmed results of a previous one conducted by the drug company, which involved 330 women.
Anastrozole is currently used to treat women after breast-cancer surgery. Treatment lasts for five years and is intended to stop the cancer from coming back, by starving the cells of hormones that could cause it.
It works by blocking the primary source of oestrogen production in women, called the aromatose enzyme pathway.
Oestrogen is the hormone that feeds tumours in many post-menopausal women.
Tamoxifen, on the other hand, works by preventing oestrogen from binding to receptors at tumour sites.
Anastrozole is not currently licensed for pre-operative breast cancer use in women.
Christine Fogg, Joint Chief Exective at Breast Cancer Care told BBC News Online: "This is potentially good news for women with breast cancer, who have been through the menopause and have oestrogen receptor positive tumours, as it may enable them to have a choice between mastectomy and breast conserving surgery."
"We would welcome more extensive research so, if appropriate, the licence for anastrozole will be made available to this particular group of women."
Around 25,000 post-menopausal women are diagnosed each year with breast cancer in the UK.
The findings were presented at the European Breast Cancer Conference in Hamburg.