Tibolone Linked to Breast Cancer Recurrence
Though synthetic steroid improves vasomotor symptoms, it still raises recurrence risk
MONDAY, Feb. 23 (HealthDay News) -- The synthetic steroid tibolone increases the risk of breast cancer recurrence, according to a report published in the February issue of The Lancet Oncology.
Peter Kenemans, M.D., of the VU University Medical Center in Amsterdam, the Netherlands, and colleagues conducted a clinical study in which 3,098 women who had undergone breast cancer surgery were randomized to receive either tibolone or placebo to relieve vasomotor symptoms. The mean time between surgery and randomization was 2.1 years, and the median study follow-up time was 3.1 years.
Compared with women who received placebo, significantly more women receiving tibolone experienced a breast cancer recurrence (10.7 percent versus 15.2 percent, respectively), the researchers report. However, no significant differences were observed between the tibolone and placebo groups regarding patient mortality (72 patients versus 63 patients, respectively), cardiovascular events (14 events versus 10 events, respectively) or gynecological cancers (10 cases in each group), the investigators found. Patients receiving tibolone did experience greater improvement in vasomotor symptoms and bone mineral density, the authors note.
"There are insufficient data to establish the safety of tibolone in women who have had breast cancer and do not require or have finished adjuvant therapy," Kenemans explains in a statement.
Schering-Plough provided funding for the study and several of the study authors are employed by the company.