Breast cancer prevention study reaches 2,000 participants mark, but more still needed

The number of women who have volunteered to take part in a Cancer Research UK breast cancer prevention study called IBIS-II has reached 2,000 but more volunteers are needed. Speaking at the National Cancer Research Institute Conference in Birmingham today, the study’s co-chairman announced that another 8,000 eligible women are needed to join the study by 2008.

Professor Jack Cuzick, the IBIS-II co-chairman who is based at Cancer Research UK’s Centre for Epidemiology, Mathematics and Statistics, said: “It is encouraging news that so many women have come forward so far to take part, as this study could provide them and future generations with a valuable option in helping to prevent and control the disease. But in order for us to gather conclusive evidence about the role of anastrozole in the prevention of breast cancer in increased risk women, we need more eligible women to come forward.”

The study* which is split into two arms has been ongoing in the UK since 2004. The IBIS-II prevention arm is the first worldwide trial to investigate whether the breast cancer treatment drug anastrozole** can prevent the disease in postmenopausal women at increased risk of breast cancer. Previous research on anastrozole as a treatment for early breast cancer

suggested that it could prevent up to 70-80 per cent of new tumours*** but to confirm its role in preventing the disease in women at increased risk, a large study on thousands of women must be conducted.

The IBIS-II prevention arm is open to women aged 40-70 years old, who have passed the menopause and are at increased risk of breast cancer, primarily because they have a family history of breast cancer. This includes women whose mother or sister had breast cancer or ovarian cancer at the age of 50 or under. Other risk factors including atypical benign breast disease may also make women eligible.

The second arm of the study, IBIS-II DCIS is the largest international trial to compare tamoxifen and anastrozole in the prevention of breast cancer recurrence in women with an early form of breast cancer called Ductal Carcinoma In-Situ (DCIS)****. Many breast cancer experts believe that hormone therapies, like tamoxifen or anastrozole, may be effective in protecting women with DCIS from developing breast cancer in the future, although they are still unclear on which therapy is best.

Professor Nigel Bundred, Professor of Surgical Oncology at Wythenshawe Hospital, Manchester said: “Anastrozole may also be the ideal candidate for women who have had a DCIS removed because it has already been proven to be better than tamoxifen at reducing disease recurrence in women diagnosed with invasive breast cancer. Now we need to see whether anastrozole will do better, and have fewer side effects, than tamoxifen for women with DCIS.”

He continued: “The DCIS trial will help to confirm which treatment is more effective in helping to prevent the disease from returning and helping women to live free from breast cancer. So we encourage more postmenopausal women who have had DCIS diagnosed and removed in the last 6 months to speak to their surgeons or consultants about volunteering for the study.”

The IBIS-II DCIS trial is open to postmenopausal women aged between 40 and 70 and who have had surgery to remove a hormone receptor positive DCIS in the last six months. Women who are found to be suitable to take part in the trial will receive either anastrozole or tamoxifen for five years.

Women can find out more about the IBIS-II study by visiting the IBIS-II website or calling the Cancer Research UK nurses on 0207 0618355.

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For media enquiries or to interview an IBIS-II spokesperson or a woman on the study please contact Rita Martins on 0207 014 0223.