London, Feb 21: Two studies on cancer drug tamoxifen have shown that it can dramatically reduce the risk of healthy women developing breast cancer.
Researchers have found that Tamoxifen, which is currently used to treat women who have already developed the disease, could lessen chance of getting the cancer for up to 20 years.
The first study, started in the 1980s, was conducted by a team of scientists led by Professor Trevor Powles the Marsden Hospital, London.
The researchers found that premenopausal women taking the drug are less likely to develop oestrogen sensitive cancer after the menopause.
"We did not initially get an effect but as time has gone on we've found a significant reduction in breast cancer - and the benefits keep getting bigger. Premenopausal women taking the drug are less likely to develop oestrogen sensitive cancer after the menopause, when they are most at risk," the Daily Mail quoted him, as saying.
The research was conducted on women in their mid-forties, who were given the drug for about six or seven years.
"This is the key to its effectiveness, because it's a relatively young population given the treatment to block the effect of oestrogen on their breasts. The side effects also seem to be less in premenopausal women," he added.
The second study confirmed that the drug continues to reduce the risk of women developing the disease by a third for several years after they have stopped taking it.
This study was conducted by the International Breast Cancer Intervention Study trial, funded by Cancer Research UK.
Scientists also found side effects such as blood clots and womb cancer stop after women finish taking the drug.
"Previous studies have already shown that tamoxifen lowers the risk of developing breast cancer during active preventive treatment. But this is the first time that clear evidence is available on the benefits and side-effects of tamoxifen after treatment with the drug has stopped," said Tony Howell, IBIS co-chair and professor of cancer prevention at the South Manchester University Hospitals Trust.
"These findings together with the effectiveness results suggest that over a longer follow-up time the risk of side-effects decreases while the benefit of prevention continues," Howell added.
Both trials were published on Feb 19 in the Journal of the National Cancer Institute. (ANI)