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for those in the EU who have wondered if tibolone is "safe" HRT
tibolone is a HRT that has estrogenic, testosterone-like and progesterone like properties and was hoped to be a safe HRT for those who had had breast cancer
It was never approved in the US and the trial of its safety in bc patients has finally been reported--
Tibolone Increases Risk of Recurrence in Breast Cancer Survivors
[Doctor's Guide]
NEW YORK — February 17, 2009 — Tibolone significantly increases the risk of recurrence for breast cancer patients, according to a study released early online and appearing in the February issue of The Lancet Oncology.
The study results suggest that tibolone should not be prescribed to any woman with known, past, or suspected breast cancer.
Peter Kenemans, Department of Obstetrics and Gynaecology, VU University Medical Centre, Amsterdam, the Netherlands, and colleagues assessed whether a dose of tibolone 2.5 mg per day increases the risk of breast-cancer recurrence in women experiencing hot flushes and associated complaints who have been surgically treated for breast cancer.
A total of 3,098 women were assessed of which 1,556 were randomised to tibolone and 1,542 to a placebo. Mean age at entry was 52.7 years, and mean time since surgery was 2.7 years.
Of the women receiving tibolone, 237 (15.2%) had a recurrence of their cancer, compared with 165 (10.7%) of the women receiving placebo — a 40% increased risk for the tibolone recipients.
The increased risk was so pronounced that the trial was stopped 6 months early. Moreover, 70% of these recurrences were distant metastases, which are invariably fatal.
ABSTRACT: Safety and efficacy of tibolone in breast-cancer patients with vasomotor symptoms: a double-blind, randomised, non-inferiority trial
[Lancet Oncology]
Background: Vasomotor symptoms and bone loss are complications frequently induced by adjuvant treatment for breast cancer. Tibolone prevents both side-effects, but its effect on cancer recurrence is unknown. The aim of this study was to show non-inferiority of tibolone to placebo regarding risk of recurrence in breast-cancer patients with climacteric complaints.
Methods: Between July 11, 2002, and Dec 20, 2004, women surgically treated for a histologically confirmed breast cancer (T1-3N0-2M0) with vasomotor symptoms were randomly assigned to either tibolone 2·5 mg daily or placebo at 245 centres in 31 countries. Randomisation was done by use of a centralised interactive voice response system, stratified by centre, with a block size of four. The primary endpoint was breast-cancer recurrence, including contralateral breast cancer, and was analysed in the intention-to-treat (ITT) and per-protocol populations; the margin for non-inferiority was set as a hazard ratio of 1·278. This study is registered with ClinicalTrials.gov, number NCT00408863.
Findings: Of the 3148 women randomised, 3098 were included in the ITT analysis (1556 in the tibolone group and 1542 in the placebo group). Mean age at randomisation was 52·7 years (SD 7·3) and mean time since surgery was 2·1 years (SD 1·3). 1792 of 3098 (58%) women were node positive and 2185 of 3098 (71%) were oestrogen-receptor positive. At study entry, 2068 of 3098 (67%) women used tamoxifen and 202 of 3098 (6·5%) women used aromatase inhibitors. The mean daily number of hot flushes was 6·4 (SD 5·1). After a median follow-up of 3·1 years (range 0·01—4·99), 237 of 1556 (15·2%) women on tibolone had a cancer recurrence, compared with 165 of 1542 (10·7%) on placebo (HR 1·40 [95% CI 1·14—1·70]; p=0·001). Results: in the per-protocol population were similar (209 of 1254 [16·7%] women in the tibolone group had a recurrence vs 138 of 1213 [11·4%] women in the placebo group; HR 1·44 [95% CI 1·16—1·79]; p=0·0009). Tibolone was not different from placebo with regard to other safety outcomes, such as mortality (72 patients vs 63 patients, respectively), cardiovascular events (14 vs 10, respectively), or gynaecological cancers (10 vs 10, respectively). Vasomotor symptoms and bone-mineral density improved significantly with tibolone, compared with placebo.
Interpretation: Tibolone increases the risk of recurrence in breast cancer patients, while relieving vasomotor symptoms and preventing bone loss.
Funding: Schering-Plough (formerly NV Organon, Oss, Netherlands).
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