The SOLE trial, involving 4,800 women worldwide, aims to determine whether taking the hormonal drug letrozole for a prolonged period helps to prevent or delay breast cancer recurring.

Studies have already shown that using the drug Letrozole can help to slow or stop the growth of oestrogen sensitive breast cancers. Women usually take hormone therapy, such as Tamoxifen or Letrozole, for five years after surgery. However, there is still a risk of breast cancer returning after this time.

The aim of this study is to determine whether the risk of recurrence can be reduced further by taking Letrozole for a another five years.

The SOLE trial will also confirm whether having a three-month break from taking Letrozole each year helps to improve its effectiveness.

For this reason, some women in the trial will take Letrozole continuously for five years, while others will take it for nine-months with a three month break each year.

To participate in this study, you must have:
• previously been diagnosed with hormone sensitive breast cancer which was also detected in nearby lymph nodes
• been treated with hormonal therapy for at least four years but not more than six years; or alternatively if hormonal therapy is completed, then have taken your last tablet less than a year ago
• completed menopause
• been free of breast cancer.

SOLE is not suitable for women who:
• Have had a bone fracture due to osteoporosis during the time they have been on hormonal therapy.
• Are using an oestrogen based hormone replacement therapy (HRT).
• Have had another cancer other than breast cancer.

If you participate in the study you will be randomly assigned to one of two groups
• Arm A – Continuous letrozole 2.5 mg tablet once a day for five years, or
• Arm B – Intermittent letrozole 2.5 mg tablet (9 months on, 3 months off) for 4 years followed by a full year of a daily letrozole tablet.

Letrozole is a drug that has been used to treat hormone sensitive breast cancer for a number of years. In some women, oestrogen promotes the growth of breast cancer cells, and a reduction in oestrogen has been shown to have a beneficial effect in women with these types of breast cancer. It belongs to a group of drugs called “aromatase inhibitors”, which work by blocking the production of oestrogen (a female hormone) in postmenopausal women.

Like all drugs it has some side effects. Participants in the study will be provided with details about the possible side effects and risks of Letrozole.

Click here for more information about the study or to register your interest to take part