The Medicines and Healthcare products Regulatory Agency (UK) warned in the February 2009 Drug Safety Advice about the increased breast cancer recurrence in patients treated with tibolone (Livial):
Treatment for breast cancer (e.g., tamoxifen) can commonly exacerbate menopausal symptoms. Although tibolone is contraindicated in women with known or suspected breast cancer, and in those with a history of breast cancer, anecdotal evidence suggests that tibolone is sometimes used off-label for treatment of vasomotor symptoms in women with a history of breast cancer; tibolone may be perceived as being safer than conventional HRT in this respect.
Recently, the LIBERATE randomised controlled trial in women with previous breast cancer was stopped 7 months early because it was unable to establish non-inferiority of tibolone compared with placebo for risk of breast cancer: importantly, it identified a significantly increased risk of breast cancer recurrence.
The advice for health professionals from the MHRA:
Tibolone (or conventional HRT) should not be used in women with known or suspected breast cancer , or in those with a history of breast cancer
See also: The Effects of Tibolone in Older Postmenopausal Women. August 2008, NEJM.