A hormone spray could reduce the chances of women at high risk of breast cancer from developing the disease.

Women who have a genetic predisposition to breast cancer currently only have the radical option of having their breasts removed to prevent cancer.

But US researchers say their research into a hormone spray could offer a less drastic option.

Women who have the gene mutations BRCA1 and BRCA2 are at a high risk of breast cancer.

Treatment which provides greater choice, is welcome news Professor Alan Ashworth, Breakthrough Breast Cancer

Both breast and ovarian cancer are often related to the action on cells by the female hormone oestrogen which appears to accumulate over a woman's lifetime.

The spray contains a drug that effectively shuts down the ovaries.

A small amount of hormones then prevents the patient from going into premature menopause.

Fertility

Details of the spray, called Libra, were revealed to a breast cancer conference in San Antonio, Texas.

It combines a drug called deslorelin with very small amounts of oestrogen and testosterone.

Doctors from the University of California and University of Utah have carried out a small trial of 13 women on the product, made by the company Balance Pharmaceuticals.

The women used a daily nose spray for a year. Within two month, their periods returned suggesting they had regained their normal fertility.

The drug mimics a hormone which "shuts down the ovary".

The hormones in the spray replace the small amount of testosterone produced by the ovaries and are equal to the smallest amount of oestrogen produced by a woman during her menstrual cycle.

Every three months, the women were given another hormone to protect the lining of the uterus, and cause period-like bleeding.

The aim of the trial was to see if it made the women's breasts easier to examine in mammograms because young women's breast tissue is dense, making it hard for X-rays to pick up tumours.

They said it may make it easier for doctors to monitor high risk patients for cancer, and could potentially prevent cancer.

Quality of life

Dr Jeffrey Weitzel, who led the study, told Reuters: "This is a regimen that preserves a woman's options.

"We have significant results already.

"In BRCA1 and 2 carriers and women without the mutations we have seen a significant decrease in breast density while bone mineral density remained stable.

"Their quality of life remained good and unchanged throughout the studies."

He said: "Our focus now is on women at high risk - not the average woman.

"But it should ultimately act as a contraceptive."

The spray is in the last stage of trials for use to treat for endometriosis.

Professor Alan Ashworth, director of the Breakthrough Breast Cancer research centre, told BBC News Online: "While the trial is still at a very early stage, the initial results look encouraging for the small proportion of women who carry the BRACA 1 or BRACA 2 gene and consequently, carry a much higher risk of developing breast cancer.

"There are a limited number of preventative options currently available to such women - vigilant screening or a prophylactic mastectomy - so a treatment which provides greater choice, is welcome news.

"We look forward to seeing how the trials progress."