Tibolone and Breast Cancer

Tibolone is a synthetic steroid marketed for the treatment of menopausal symptoms. A cohort study of women with no history of breast cancer showed that tibolone was associated with an increased risk of breast cancer. In women with a history of breast cancer, a placebo-controlled trial showed a higher risk of breast cancer recurrence with tibolone. A placebo-controlled trial of half the standard dose of tibolone showed no increased risk of breast cancer but was interrupted due to an increased risk of stroke. In practice, it is better simply not to use tibolone.