A trial looking at different hormone therapies for premenopausal women with breast cancer (TEXT)

Cancer type:

Breast cancer

Status:

Results

Phase:

Phase 3

This trial was looking at a drug called triptorelin with either tamoxifen or exemestane after surgery for breast cancer. It was for women who had not yet been through the menopause. The trial was supported by Cancer Research UK.

Some breast cancers are oestrogen receptor positive Open a glossary item (or ER positive). This means they grow in response to the hormone oestrogen. In women who haven’t been through the menopause , oestrogen is made in the ovaries . After the menopause, the ovaries no longer make oestrogen, but a small amount is produced in fat tissues and by the adrenal glands Open a glossary item .

Doctors usually treat premenopausal women who have ER positive breast cancer with the hormone therapy drug tamoxifen, alongside other treatments such as surgery, radiotherapy or chemotherapy. Tamoxifen blocks receptors on breast cancer cells and helps to stop the cancer coming back after surgery.

Another group of drugs used to treat ER positive breast cancers are aromatase inhibitors. These drugs work by reducing the amount of oestrogen the body makes. They don’t block oestrogen made by the ovaries. But they block the small amounts made in fat tissues and the adrenal glands in women who have been through the menopause.

In this trial, the researchers wanted to see how well the aromatase inhibitor, exemestane worked for women who had not been through the menopause.

As their ovaries were still working, the women also had treatment to ‘switch off’ their ovaries and stop them making oestrogen. Switching off the ovaries is called ovarian function suppression or OFS.

One way of switching off the ovaries is to use a drug called triptorelin. Doctors think that doing this will help exemestane to work in premenopausal women with breast cancer.

Everyone in this trial had triptorelin to stop their ovaries working. Some also had tamoxifen and some had exemestane. The aim of this trial was to see which treatment was better at stopping breast cancer coming back after surgery in premenopausal women.

Summary of results

The researchers found that more women who had exemestane and ovarian function suppression (OFS) were free of breast cancer after 5 years than women who had tamoxifen and OFS.

The trial recruited 2,672 women. They had all had treatment for early breast cancer.

It was a randomised trial. The women taking part were put into 1 of 2 groups at random.

1,338 were randomised to have exemestane and triptorelin
1,334 were randomised to have tamoxifen and triptorelin

TEXT trial randomisation diagram

A small number of women never started treatment, or the trial team don’t have results for them. But the researchers analysed the results from this trial along with results from another trial that looked at exemestane or tamoxifen and ovarian function suppression (OFS). The other trial was called the SOFT trial.

By looking at both trials together, they were able to compare the results from more than 4,600 women.

They looked at the number of women in both trials who were living without any signs of breast cancer after 5 years. Doctors call this disease free survival. They found it was

91% of the women who had exemestane and OFS
87% of the women who had tamoxifen and OFS

SOFT & TEXT trial diagram

The researchers need to follow up the women for longer to see if there is a difference in how long they live overall. Doctors call this overall survival.

Nearly all the women had hot flushes during treatment. Many had problems with their muscles, bones or joints, but this side effect was more common in the group having exemestane. Less than a third of the women in each group had serious side effects. This is about the same as when post menopausal Open a glossary item women have these drugs.

The combined results of the TEXT and SOFT trials show that more premenopausal women who had treatment with exemestane and OFS were free of breast cancer after 5 years than women who had tamoxifen and OFS.

We have based this summary on information from the team who ran the trial. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.