It is estimated that the treatment will save thousands of lives and offer prevention without side-effects for healthy women in their thirties who have a family history of breast cancer or a genetic predisposition to the disease.
The findings, presented yesterday at the American Society of Clinical Oncology in Atlanta by Michael Baum, professor of surgery at University College London, show that for women who have had breast cancer, there is a 50 per cent reduction in the risk of developing it in the other breast if they are given the drug, goserelin.
"This is very exciting and opens up a whole new possibility of preventing breast cancer in high-risk young women. If the drug can prevent cancer developing in the other breast of women who have had breast cancer then it could be used for healthy women who are at high risk of developing breast cancer," said Professor Baum, who is also head of the Cancer Research Campaign breast cancer trials group. "This opens up a new chapter in prevention," he said.
The doctors believe that goserelin, sold under the brand name Zoladex by Zeneca Pharmaceuticals, has greater benefits than existing breast cancer drug treatments, such as Tamoxifen, because of the lack of side- effects. Zoladex works by stopping the production of oestrogen, the female sex hormone. It does this byswitching off the ovaries without permanently damaging them. Often when relatively young women contract breast cancer it is because they are sensitive to oestrogen, which can trigger tumour growth.
A young healthy women at risk could go on the drug for several years, and come off when she wanted to have a child, with no adverse effects. Tamoxifen has been very successful in treating breast cancer but is primarily used by women who have passed the menopause. Although it also reduces the risk of women getting cancer in the other breast it has several side- effects such as increasing the risk of developing cancer of the womb.
The international trial involved 2,631 women, who were under 50 years old, from Britain, Italy and Sweden. Allhad undergone standard treatment for the disease, and then a random sample were given monthly injections of Zoladex. As well as halving the risk of developing cancer in the other breast, the drug also improved the survival rate for the existing cancer.
Nine out of 10 women given the drug remained symptom free after four years. Of those who did have a relapse, 261 received goserelin compared with 330 who did not, a statistically significant difference.
One woman in 11 will develop breast cancer during her lifetime.Reuse content