4 October 2004
Dundee Centre seeks women for preventing breast cancer trial
Scientists based at the University of Dundee are today (Monday) calling for women help them take the
next big step towards preventing breast cancer by taking part in a major new trial called IBIS II*, which
is funded by Cancer Research UK.
The ten year study will test a new drug called anastrozole and involve 10,000 healthy post-menopausal
women who are at an increased risk of the disease. Anastrozole has already been shown to be an effective
hormone treatment for breast cancer but this will be the first time the drug has been examined as a
preventive measure.
Researchers believe that, in post-menopausal women, anastrozole could reduce the risk of breast cancer
by more than 50 per cent. Around 30,000 postmenopausal women are diagnosed with the disease in the UK
annually, so if successful this intervention could lead to several thousand fewer women developing breast
cancer each year.
*International Breast cancer Intervention Study II
The trial follows the successful IBIS-I study which showed that tamoxifen reduces the incidence of
breast cancer by a third in women at a higher risk of the disease.
During trials of anastrozole as a treatment for early breast cancer2, researchers noticed that women
taking the drug were around 40 per cent less likely to be diagnosed with a second cancer in the opposite
breast compared to women taking tamoxifen.
Over 50 centres are now open for recruitment worldwide, including over 30 in the UK. The international
research team will be led by Professor Jack Cuzick, Director of Cancer Research UK's Department of
Mathematics, Statistics and Epidemiology based at Queen Mary, University of London.
He explains: "The results of the earlier IBIS-I trial showed that preventing breast cancer is a real
possibility, but the new trial has the potential to have an even more dramatic impact on the disease."
Both anastrozole and tamoxifen work by interfering with the female hormone oestrogen, which is known
to be the most important cause of breast cancer.
Tamoxifen works by preventing the action of oestrogen on the cells of the breast while maintaining the
beneficial effects of oestrogen on bone. However, tamoxifen also produces oestrogen-like effects on the
cells of the endometrium (womb lining) and is linked to a slightly higher rate of endometrial cancer and
a tendency to thrombosis (blood clots).
Unlike tamoxifen, anastrozole actually prevents the production of oestrogen in post-menopausal women
and seems to have fewer side effects.
Compared to tamoxifen, women taking anastrozole experience fewer hot flushes. However, anastrozole
does not have the beneficial effects of tamoxifen on bones and this will be carefully monitored and
managed within the trial.
Professor Cuzick adds: "It's vital that in trying to prevent breast cancer we balance the beneficial
effects of a drug with any potential side effects.
All drugs have side effects but anastrozole has fewer than tamoxifen and in particular it doesn't show
the slightly increased risk of blood clots or womb cancer."
Professor Alastair Thompson, Professor of Surgical Oncology at Ninewells Hospital and Medical School
is leading the trial in Dundee and explains: "To be eligible for IBIS II, women must be post-menopausal,
not taking HRT and have at least twice the normal risk of breast cancer - for example someone whose
mother or sister had breast cancer before the age of 50, or who has two family members with the disease.
The trial will compare anastrozole with a placebo and look at how many women develop breast cancer as
well as any side effects of the drug.
It will be the first opportunity for women to take anastrozole as a preventive measure. Although only
half of the women on the trial will receive the new drug, all of the women will receive a bone scan, breast
screening every 18 months and the best available care and monitoring.
Post-menopausal women who are interesting in taking part should contact our research nurses, Gillian
Little and Mhairi Hawkes on 01382 633850."
Among the 10,000 recruited, 4,000 will be women who have been diagnosed with a non-invasive form of
breast cancer, called DCIS. As well as being at an increased risk of developing fully invasive breast
cancer, these women are also more likely to develop a new tumour in the opposite breast.
This section of the trial is designed to find out whether anastrozole can prevent the occurrence of
new cancers, both in the breast affected by DCIS and the opposite one when compared to tamoxifen.
Kate Law, Cancer Research UK's Head of Clinical Trials, says: "With the incidence of breast cancer
rising year on year it's vital that we consider ways to prevent the disease.
Anastrozole looks like a very promising option but the only way we will know for sure is to carry out
this large scale trial. If the drug lives up to its promise thousands of cancers could be prevented in
the UK alone.
For media enquiries please contact Angela Kilday, Cancer Research UK Scotland on 0131 311 4808 or 0771
368 7200 or Jenny Marra, University of Dundee on 01382 344910.
Notes to editors
1. Anastrozole's trade name is Arimidex. It is one of a group of drugs called aromatase inhibitors. In
post-menopausal women, an enzyme called aromatase plays a key role in the production of oestrogen. The
ATAC study - Arimidex and Tamoxifen Alone or in Combination.
2. Ductal carcinoma in situ (DCIS) is a form of breast cancer in the milk ducts. As these cells are
contained within the ducts, there is very little chance that any of the cells have spread to the lymph
nodes or elsewhere in the body. Some doctors describe DCIS as a very early form of breast cancer, others
call it a pre-cancerous condition because it often develops into an invasive cancer if it is not treated.
These cases are usually only detected by mammographic screening, where they represent about 20 per cent
of the detected abnormalities (approximately 2,700 women each year).
3. Ductal carcinoma in situ (DCIS) is a form of breast cancer in the milk ducts. As these cells are
contained within the ducts, there is very little chance that any of the cells have spread to the lymph
nodes or elsewhere in the body. Some doctors describe DCIS as a very early form of breast cancer, others
call it a pre-cancerous condition because it often develops into an invasive cancer if it is not treated.
These cases are usually only detected by mammographic screening, where they represent about 20% of the
detected abnormalities (approximately 2,700 women each year).
For more information on the trial log on to the IBIS website
(www.ibis-trials.org) or CancerHelp UK (www.cancerhelp.org.uk)
or write to:
The Information Nurses
Cancer Research UK
P.O.Box 123
Lincoln's Inn Fields
London
WC2A 3PX
4. October is Breast Cancer Awareness Month. Cancer Research UK is the major funder of research into
breast cancer in the UK. For more information log on to www.cancerresearchuk.org/breastcancer/
By Jenny Marra, Head of Press 01382 344910, out of hours: 07968298585, j.m.marra@dundee.ac.uk | 
