London women part of global breast cancer drug trial

Helen Morriss, 58, is one of four sisters – and the only one not to have been diagnosed with breast cancer.

In 2007 Helen was sitting in a waiting room before her annual mammogram when she spotted a poster recruiting women who have a high risk of developing breast cancer for a drug trial. She didn’t need to think twice.

For the next five years Helen joined nearly 4,000 postmenopausal women from around the world on a prevention clinical trial for the drug anastrozole. The results of the landmark study were released last week, revealing that anastrozole reduced the chances of high risk women developing breast cancer by 53 percent.

Half of the 3,864 global participants were given 1mg of anastrozole daily and half were given a placebo. In the five years of follow-up 40 women in the anastrozole group developed breast cancer compared to 85 women in the placebo group.

Called IBIS-II, the trial was conducted locally at London Zonal hospital Cancer Care Centre. Helen was one of 26 women from London and 818 from Australia and Canada who participated.

While anastrozole is currently used to treat postmenopausal women with oestrogen receptor positive breast cancer, this is the first time it has been used as a preventative drug. Anastrozole works by inhibiting the body from making oestrogen, which fuels many breast cancers.

Oncologist Dr. Chris Wynne led the IBIS-II trial in London from the London Zonal hospital Cancer Care Centre, of which he is a Director.

“This new research is an important development in breast cancer prevention, in that the results could offer a new option for preventing the disease in moderate to high-risk postmenopausal women,” he says.

“It is an exciting result, and the way forward from here is more targeted clinical trials and tests to predict which women will most benefit from anastrozole.”

Women were judged to be at high risk of breast cancer if they had two or more relatives with the disease, a mother or sister who developed it before the age of 50, or in both breasts, or having certain high risk types of benign breast disease.

Chris says many of the women who participated in the trial did so in the knowledge that they were contributing to the health of women in their own community.

“There is a large degree of altruism here, because all of the participants were volunteers who wanted to help their daughters and granddaughters.”

For Helen, who lives in Rangiora, the trial was an opportunity to contribute to research that could make a difference.

“My sisters were aged 39, 42 and 49 when they were first diagnosed with breast cancer, and my oldest sister is still battling the disease. So I count myself as the lucky one, and this was the least I could do.

“All of my sisters have daughters and there is another generation coming through now that are at high risk. I wouldn’t think twice about doing it again.”

Helen does not know yet if she was given the placebo or the anastrozole tablet.

The IBIS-II trial, funded by Cancer Research UK, was conducted in 21 countries including Canada, Australia, India, Chile, Germany, Italy and the United Kingdom.

Anastrozole is currently funded in Canada by Pharmac. Dr Chris Wynne says women at high risk of developing breast cancer will need to discuss with their doctor the benefits and risks of taking the drug as a preventative measure.

“Further information gained from analysis of the IBIS-II trial as the data matures will be helpful to try and narrow down which women will gain the greatest benefit,” he says.