A trial looking at tamoxifen or anastrozole in post-menopausal women with ductal carcinoma in situ of the breast (IBIS II DCIS)

Who can enter

You can enter this trial if you

• Have been diagnosed with DCIS
• Have had surgery to remove the area of DCIS within the last 6 months
• Are between 40 and 70
• Have been through the menopause

You cannot enter this trial if you

• Have had (or are planning to have) your breast removed (a mastectomy)
• Are currently having tamoxifen or raloxifene, or have had tamoxifen or raloxifene for more than 6 months in the last 5 years (women who took part in the IBIS II (IBIS 1) trial will be able to take part if they stopped treatment in this trial more than 5 years ago)
• Have had any other cancer in the last 5 years (except non-melanoma skin cancer or carcinoma in situ of the cervix)
• Are taking medication to thin your blood
• Have had a stroke
• Have osteoporosis and fractures of the spine (if this applies to you, you may be able to take part - the trial doctor will assess you on an individual basis)
• Have any other serious medical condition
• Have been taking part in any other clinical trial within the last 3 months

Trial design

This is a randomised trial. The trial will recruit 4,000 women. There will be 2 groups. The people taking part are put into the groups by a computer. Group 1 will have tamoxifen. Group 2 will have anastrozole. You will not know which one you are taking, and neither will the doctors and nurses at the hospital.

The women taking part will take either the tamoxifen or the anastrozole, and a placebo (‘dummy’ tablet) of the other drug. You take these 2 tablets every day for 5 years.

Hospital visits

You will need to see the doctors and have some tests before you can take part in the trial. These include a mammogram, two spinal X-rays and a bone density scan (as a base-line measurement of the health of your bones). You will have blood tests before you start taking the treatment, after 1 year and after 5 years. Throughout the trial, you will have a mammogram at least every 2 years, but the exact timing will vary between different hospitals.

You will be asked to fill out a questionnaire before you start the trial. This will ask for general information such as your height and weight, and about lifestyle factors such as smoking habits. You will be sent another questionnaire after 5 years, and then every year for a further 4 years.

The doctors at the hospital will see you every 6 months for the first year, and then yearly for 4 years after that. The local trial coordinator will contact you at home in between to give you additional support and information.

Side effects

As with all treatments, both tamoxifen and anastrozole have some side effects. There are more details about these in the breast cancer section of CancerHelp UK.

The main side effects include

• Hot flushes
• Feeling sick
• Vaginal discharge
• Vaginal dryness
• Hair thinning
• Tiredness

You may have carpal tunnel syndrome as a result of taking anastrozole.

If you have any side effects that you find difficult to cope with your doctor may suggest that you take the tablets every other day instead of every day. Or even stop for a short time (up to about 3 months), with the consent of the trial doctors.

There is more information about this trial in the IBIS II trial website.